Jerry’s Favs from the Recent 7th Cambridge Symposium

  • DNA Can Function as an Enzyme
  • RNA Polymerase Activity Without Proteins
  • Systemic Brain Delivery of Therapeutic Oligos

The 7th Cambridge Symposium on Nucleic Acids Chemistry and Biology took place September 3-6, 2017 at historic Queens’ College, Cambridge, which was founded in 1448 by Margaret of Anjou (who was then Queen of England by marriage to King Henry VI). Yours truly had the honor of participating in this event and presenting one of TriLink’s posters on the company’s new types of chemically modified mRNA for mRNA therapeutics. As done for other conferences I’ve attended on behalf of TriLink, I wish to share here my personal favorites among the many lectures, which are still fresh in my mind. However, I hasten to emphasize that, while choosing these “favs” is biased a bit by my scientific interests, all the lectures topics are worth looking at later by perusal of the symposium program of nearly forty presentations.

Taken from na-cb.co.uk

By the way, the symposium’s logo artistically depicts a DNA helix under a wooden bridge, better seen in the accompanying picture of the actual bridge over the River Cam at Queens’ College. Built in 1749, it has become known as the Mathematical Bridge for reasons you can read later, and appears to be an arch but is composed entirely of straight timbers. The historical connection between the DNA double helix and Cambridge is that in 1953 Watson & Crick proposed this now famous deoxynucleic acid structure as the molecular basis for genetics, which I’ll comment on again at the end of this post.

Taken from worldachitecture.org

Overview of the Symposium

Mike Gait. Taken from histmodbiomed.org

This symposium is the 7th in a popular conference series going way back to 1981 that brings together nucleic acids scientists across a broad area but with emphasis on chemistry, biochemistry and structure. Michael (Mike) Gait, who is at the Medical Research Council Laboratory of Molecular Biology in Cambridge, originated this series and has been a key organizer for all seven conferences. Participants come from all over the world and include professors, students, and companies—as well as Nobel Laureates (this year Jack Szostak of telomeres fame).

In addition to Mike, the organizing committee included Sir Shankar Balasubramanian, who was recently knighted for his contributions to next-generation sequencing and research on G-quadruplexes, the latter of which I featured here a few years ago. Other committee members were Rick Cosstick, Phil Holliger, and Chris Lowe.

Subject areas this year included:

  • Nucleic acids as therapeutics (including antisense, RNAi, aptamers, immune recognition, cell delivery)
  • RNA and DNA structures and their protein complexes (duplexes, quadruplexes, RNA and DNA enzymes, riboswitches, protein complexes + assemblies)
  • Nucleic acids chemistry applied to cells and cell mechanisms (genomes, evolution, repair, cell manipulation)
  • Nucleic acids as tools, structural assemblies and devices (nanostructures, cages, arrays, supra-molecular chemistry)

Marv Caruthers. Taken from colorado.edu

The showcased and highly prestigious Nucleic Acids Award was presented to Marvin (“Marv”) Caruthers in recognition of his seminal contributions to the synthesis of oligodeoxynucleotides (aka “oligos”) based on the use of phosphoramidite chemistry. This mechanistically elegant chemistry enabled much faster and more efficient coupling for automated synthesis of oligos, which fundamentally transformed all manner of basic and applied research with DNA. His award lecture was titled Synthesis, Biochemistry, and Biology of New DNA Analogues, some of which has been recently published. My previous several posts commenting on Marv, who has been a professor at the University of Colorado in Boulder since 1973, can be read later here.

Jerry’s Favs from the Symposium

To encourage inclusion of unpublished results and other types of “late breaking news” from the lab, the organizers forbade use of Twitter or other real-time social media, blogging, or taking pictures of slides being shown. Consequently, what I can say here is restricted to published papers related to my favs. Keeping this limitation in mind, here are my personal top-three talks that I consider to be tied (i.e., have equivalent scientific importance).

DNA Can Function as an Enzyme!

This lecture by Scott Silverman at the University of Illinois, Urbana-Champaign, dealt with DNA enzymes (aka deoxyribozymes), which were first reported in 1996 by Carmi et al., and are of interest because they expand enzymatic functionality from naturally occurring proteins to synthetic nucleic acids. DNA enzymes can be evolved in vitro starting with random sequences of DNA and applying suitable selection.

In a published account titled Pursuing DNA Catalysts for Protein Modification, Silverman has provided a lengthy and chemically detailed description of his use of in vitro selection to develop DNA catalysts for many different covalent modification reactions of peptide and protein substrates. While interested readers can consult Silverman’s account for various examples, it’s illustrative to consider the molecular design strategy depicted below that was used to evolve a synthetic DNA functional-equivalent of naturally occurring protein kinases that, by definition, carry out protein phosphorylation.

Taken from Silverman Acc Chem Res (2015)

In this case, modular deoxyribozyme design involved a stretch of 40 randomized bases (N = A/G/C/T) having a hairpin loop conjugated to a tyrosine (Tyr)-containing peptide on one end, and an ATP-binding aptamer on the other end. This was intended to experimentally assess whether it would be helpful to provide a predetermined small-molecule binding site in the form of an aptamer, which would cooperate functionally with an initially random catalytic region (N40) from the onset of selection. The selection outcome established that while modular deoxyribozymes that utilize a distinct predefined aptamer domain can indeed be identified, such DNA catalysts do not have any functional advantage relative to nonmodular analogues selected simultaneously for binding and catalysis, at least for this test case of tyrosine kinase activity using an ATP phosphoryl donor.

RNA Polymerase Activity Without Proteins!

By analogy to use of in vitro selection to evolve DNA enzymes from complex pools of random sequences of DNA, complex mixtures of unrelated RNA sequences can also be subjected to in vitro selection to evolve RNA enzymes (aka ribozymes). Indeed, as noted and cited in a talk by co-organizer Philipp Holliger, the emergence of an RNA catalyst capable of self-replication is considered a key transition in the origin of life in the prebiotic “RNA World” first hypothesized by Walter Gilbert in the 1980s. How such self-replicating (replicase) ribozymes emerged from the pools of short RNA oligomers arising from prebiotic chemistry and non-enzymatic replication, however, is unclear.

In a published version of Holliger’s talk addressing this important open question, his laboratory carried out an elegant series of experiments demonstrating that RNA polymerase ribozymes can assemble from catalytic networks of RNA oligomers that are each no longer than 30 nucleotides. Additionally, they found that entropically disfavored assembly reactions are driven by iterative freeze-thaw cycles. Such cooling (to freeze)-warming (to melt) cycles for aqueous solutions of RNA oligo reactants are notionally opposite to heating (to dissociate)-cooling (to hybridize) cycles used for amplification by PCR.

Interested readers can peruse Holliger’s publication for details about these novel findings, but for the purposes of this blog the schematic shown below depicts and describes the mechanism for assembly wherein relatively short RNA oligomers undergo serial ligations and “grow” into a self-replicating RNA polymerase. To me, these results provide an amazing glimpse backward in time to how the RNA World may have evolved!

Assembly of a RNA polymerase ribozyme (RPR 1234) from oligonucleotides devoid of pre-activation. (a) Schematic representation of the assembly trajectory involving (anti-clockwise from top left), ribozyme (blue) cleavage of a short 3′ tail (red) generating a 2′, 3′ cyclic phosphate (>p) (red dot), dissociation of the cleaved tail and strand exchange to cognate substrate (orange) followed by ligation of substrate 5′ OH with >p. (b) Network diagram of RPR 1234 assembly from 4 tailed fragments 1, 2, 3 and 4. Tailed input fragments can ligate to their cognate 5′fragments but must be cleaved (red lines) before ligation to 3′fragments. Taken from Holliger Nat Chem (2015).

Systemic Brain Delivery of Therapeutic Oligos!

Taken from igtrcn.org

A talk by Fazel Shabanpoor titled Identification of a Peptide for Systemic Brain Delivery of a Morpholino Oligonucleotide in Mouse Models of Spinal Muscular Atrophy described work that he had just published with a group of collaborators that included symposium co-organizer Mike Gait, whose lab interests have recently focused on cell-penetrating peptides. This was a fav for me because it had multiple interesting elements: (1.) systemic brain delivery, which is a widely recognized challenge; (2.) “weirdly” structured morpholino oligos, which have backbone structures quite unlike DNA that I’ve commented on here previously; and (3.) splice-switching antisense oligos (SSOs). The latter class of molecules (SSOs) base-pair with a pre-mRNA and disrupt the normal splicing repertoire of the transcript by blocking the RNA–RNA base-pairing or protein–RNA binding interactions that occur between components of the splicing machinery and the pre-mRNA. Readers interested in SSOs—currently a “hot topic”—can consult a recent comprehensive review, while SSOs for spinal muscular atrophy (SMA) has been featured in previous blog here.

Shabanpoor’s lecture highlighted the fact that development of systemically delivered antisense therapeutics has been hampered by poor tissue penetration and cellular uptake, including crossing of the blood–brain barrier (BBB) to reach targets in the central nervous system (CNS). For SMA application, Shabanpoor et al. investigated the ability of various BBB-crossing peptides for CNS delivery of a splice-switching 20-mer phosphorodiamidate morpholino oligonucleotide (PMO) targeting survival motor neuron 2 (SMN2) exon 7 inclusion. They identified a branched derivative of the well-known ApoE (141–150) peptide, which as a PMO conjugate was capable of exon inclusion in the CNS following systemic administration, leading to an increase in the level of full-length SMN2 transcript.

Treatment of newborn SMA mice with this peptide-PMO (P-PMO) conjugate resulted in a significant increase in the average lifespan and gains in weight, muscle strength, and righting reflexes. Systemic treatment of adult SMA mice with this newly identified P-PMO also resulted in small but significant increases in the levels of SMN2 pre-messenger RNA (mRNA) exon inclusion in the CNS and peripheral tissues. It was concluded that this work provides proof of principle for the ability to select new “peptide paradigms to enhance CNS delivery and activity of a PMO SSO through use of a peptide-based delivery platform” for the treatment of SMA potentially extending to other neuromuscular and neurodegenerative diseases.

Parting Thoughts and The Eagle

I hope that you can now appreciate why these three lectures were my favs from the 7th Cambridge Symposium. Silverman’s conversion of DNA into an enzyme that can phosphorylate a protein is an exciting demonstration of the power of bio-organic chemistry to manipulate DNA to do things it can’t do naturally. Holliger’s demonstration of how RNA polymerase ribozymes may have evolved gives credence to the RNA World hypothesis, and indicates that this supposed prebiotic environment may have provided critical freezing and thawing cycles over many millennia of molecular evolution. In the present biotic world, humans afflicted with neuromuscular and neurodegenerative diseases may benefit from Shabanpoor & Gaits’ new peptide paradigms to enhance CNS delivery and activity of therapeutic oligos.

In conclusion, I should mention that researchers who work with DNA will invariably visit The Eagle when in Cambridge, which is a pub only a short walk from Queens’ College. This pub, which dates back to 1667, is quite famous because it is known with certainty to be the place where Francis Crick interrupted patrons’ lunchtime on February 28, 1953 to announce that he and James Watson had ‘discovered the secret of life’ after they had come up with their proposal for the structure of DNA. Today the pub serves a special ale dubbed “Eagle’s DNA” to commemorate the discovery. Trust me when I say that this ale is mighty tasty, because I enjoyed a pint of it, and while standing in the que for that brew, was inspired to capture this image to share here.

As usual, your comments are welcomed.

Personal photo using a Samsung Galaxy S8

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National ALS Advocacy Day

  • Tuesday May 16, 2017 is National ALS Advocacy Day
  • Mark Your Calendar and Get Involved!
  • Read on to Find Out Why Involvement Matters

Lou Gehrig (1903-1941). Taken from Wikipedia.org

Amyotrophic lateral sclerosis (ALS) is more commonly referred to in North America as “Lou Gehrig disease.” Henry Louis “Lou” Gehrig was a record-setting baseball All-Star for the New York Yankees from 1923 through 1939, when he voluntarily took himself out of the lineup to stunned fans after his play was hampered by ALS. Sadly, Mr. Gehrig died only two years later, which indicates the rapidity of ALS disease progression.

ALS was first found in 1869 by French neurologist Jean-Martin Charcot, but it wasn’t until Lou Gehrig’s affliction that national and international attention was brought to the disease. ALS is now known to be a group of neurological diseases that mainly involve the degeneration of nerve cells (neurons) responsible for controlling voluntary muscle movement, like chewing, walking, breathing and talking. Motor neurons are nerve cells that extend from the brain to the spinal cord and to muscles throughout the body.

Taken from irelandms.com

The disease is relentlessly progressive, meaning the symptoms get continuously worse over time. Both the upper motor neurons in the brain and the lower motor neurons in the spine degenerate or die, and stop sending messages to the muscles. Unable to function, the muscles gradually weaken, start to twitch, and waste away (atrophy). Eventually, the brain loses its ability to initiate and control voluntary movements.

Currently, there is no cure for ALS and no effective treatment to halt, or reverse, the progression of the disease. Most people with ALS die from respiratory failure, usually within 3 to 5 years from when the symptoms first appear. However, about 10 percent of people with ALS survive for 10 or more years.

It is generally estimated there are over 30,000 people living with ALS in the United States at any given time, and that the number worldwide is around 450,000. Someone is diagnosed with ALS every 90 minutes. The life-time incident rate for an average person is often estimated at between 1-in-400 to 1-in-600 people—an incidence rate comparable to that for multiple sclerosis.

Who Gets ALS and Why?

Following are some reliable facts that I selected from an authoritative NIH website for ALS:

  • ALS affects people of all races and ethnic backgrounds.
  • Caucasians and non-Hispanics are most likely to develop the disease.
  • Although the disease can strike at any age, symptoms most commonly develop between the ages of 55 and 75.
  • Men are slightly more likely than women to develop ALS. However, the difference between men and women disappears with aging.
  • Military veterans are about 1.5 to 2 times more likely to develop ALS, and is recognized as a service-connected disease by the U.S. Department of Veterans Affairs.
  • 90% of ALS cases are considered sporadic, i.e. the disease seems to occur at random.
  • 10% of ALS cases are familial, i.e. an individual inherits the disease from his or her parents.
  • Mutations in more than a dozen genes have been found to cause familial ALS

How is ALS treated?

Riluzole. Taken from healthtap.com

No cure has yet been found for ALS. However, there are treatments available that can help control symptoms, prevent unnecessary complications, and make living with the disease easier. In 1995, the FDA approved riluzole (Rilutek), the only disease-modifying drug to date for ALS. Riluzole has multiple neural mechanisms of action, and is believed to reduce damage to motor neurons by decreasing levels of glutamate, which transports messages between nerve cells and motor neurons. Unfortunately, clinical trials in people with ALS showed that riluzole prolongs survival by only a few months.

BrainStorm Cell Therapeutics & NurOwn®

In researching clinical trials for hopefully much more effective therapies for ALS, I came across a company in Israel named BrainStorm Cell Therapeutics Inc. (BCTI) that offers a form of stem cell therapy for ALS that appears to be quite promising. Following is a short synopsis of what I found.

Space-filling model of BDNF. Taken from Wikipedia.org

BCLI has developed a patented stem cell-based technology that delivers a growth factor that can help neurons live longer at or near the site of injury or damage. More specifically, a mesenchymal stem cell isolated from an ALS patient is grown in a cell culture under certain conditions to produce a differentiated phenotype that secretes brain-derived neurotrophic factor (BDNF) at a level at least five-times greater than normal. The term “factor” is generic in biomedical parlance, and in the case of BDNF refers to a protein pictured to the right.

After these “super secreting” cells are obtained ex vivo, they are reintroduced (aka implanted) into the same ALS patient (i.e. an autologous transplant; see schematic diagram) wherein BDNF acts on neurons of the central nervous system and the peripheral nervous system, helping to support the survival of existing neurons, and encourage the growth and differentiation of new neurons and synapses.

Taken from Byrne JA. Overcoming clinical hurdles for autologous pluripotent stem cell-based therapies. OA Stem Cells 2013 Sep 01;1(1):3.

Details for this cell-harvesting, ex vivo differentiation, selection, and implantation can be read in this 2014 article by BCTI in Clinical Translation Medicine. BCTI has registered these differentiated BDNF-secreting cells as NurOwn®, which I assume is intended to sound bit like “your own”—to reflect the autologous nature of the transplant—and be a linguistic blend of neuron and own. In any case, the important point is that safety and efficacy have been reported in a recently published Phase 1/2 and 2a open-label, proof-of-concept studies of patients with ALS at the Hadassah Medical Center in Jerusalem, Israel.

In the Phase 1/2 part of the trial, 6 patients with early-stage ALS were injected intramuscularly (IM) and 6 patients with more advanced disease were transplanted intrathecally (IT), i.e. via the spinal cord. In the Phase 2a dose-escalating study, 14 patients with early-stage ALS received a combined IM and IT transplantation of autologous BDNF-secreting cells. Interested readers can consult this publication for details, but the bottom line, if you will, was that the possible clinical benefits would be hopefully confirmed in an upcoming clinical trial.

My further research on this led to a February 2017 press release by BCTI announcing that City of Hope’s Center for Biomedicine and Genetics (CBG) in Duarte, California will produce clinical supplies of NurOwn® adult stem cells for the BCTI’s planned randomized, double-blind, multi-dose Phase 3 clinical study in patients with ALS. It added that CBG is expected to support all U.S. medical centers that will be participating in the Phase 3 trial.

A second February 2017 press release by BCTI announced an agreement with Centre for Commercialization of Regenerative Medicine (CCRM) in Toronto, Canada to support the market authorization request for NurOwn® and explore the opportunity to access Health Canada’s early access pathway for treatment of patients with ALS as early as 2018.

Other ALS Clinical Studies

My “go to” authoritative source of reliable information about clinical trials is NIH’s ClinicalTrials.gov website that has an updated database that can be searched and filtered in many ways. When I searched for ALS clinical trials that were recruiting patients, I was heartened to find over 180 studies that can be perused via this link. For each study, there is information about purpose, study design and measures, eligibility, contacts and locations.

Incidentally, as regular readers of my blog will know, modified mRNA (mod mRNA) therapeutics is a relatively new and very promising modality for treating diseases that respond to providing or supplementing proteins. Given that DNA vectors encoding BDNF mRNA are readily available, I’m hoping that a mod mRNA for BDNF will soon be investigated as yet another avenue of treatment for ALS.

Advocate for ALS!

Taken from alsa.org

The ALS Association (ALSA) has the stated mission “to discover treatments and a cure for ALS, and to serve, advocate for, and empower people affected by ALS to live their lives to the fullest.” ALSA’s website offers various ways for any individual to become an advocate for ALS, such as becoming informed and donating much needed money or time, participating in the Walk to Defeat ALS® that draws people of all ages and athletic abilities together (see picture) to honor the courageous souls who are affected by ALS, to remember those who have passed, and to show support for the cause.

One of my long-time friends has recently been diagnosed with ALS, which in part led me to research this blog to help inform him, and led me to find a Walk to Defeat ALS® in which to participate. I encourage you to do advocate for ALS in whatever way you wish and are able.

As usual, your comments are welcomed.

RNA and DNA Examples of ‘Seek, and Ye Shall Find’

  • New RNA Modification Found in the Epitranscriptomic Library for Mammals
  • Ditto for a DNA Modification in Mammalian Epigenetics
  • What Will ‘Ye’ Find Next with Improved RNA and DNA Analytical Methods?

‘Seek, and ye shall find’ is a biblical quote (Matthew 7:7) that many might say is a self-evident statement indicating that to find something you need to look for it. In any case, I used it as a segue for us scientists to remember that our collective understanding of RNA and DNA is limited, in part, by the analytical tools we use for these nucleic acid molecules. To me this predicament is akin to a person under the lamp post at night being limited to find whatever is illuminated, and miss what is not. The old cartoon below conveys a humorous variant of this. But I digress…

Taken from quoteinvestigator.com

Taken from quoteinvestigator.com

In previous postings here, I’ve commented on new illuminations—pun intended—for RNA modifications, such as pseudouridine, about which understanding of function is just emerging. And likewise for congeners of the 5-methyl group of cytidine in DNA, such as 5-hydroxymethyl or 5’-formyl moieties.

To continue this metaphor—but to get to the point—the lamp post’s light-field has been recently expanded to allow researchers to now find previously unseen modified bases in mammalian RNA and DNA, namely, N1-methyladenosine and N6-methyl-2’-deoxyadenosine, respectively. Briefly, here’s what’s been reported.

Expanding Epitranscriptomics

Just like modification of bases in DNA after its replication leads to what’s called epigenetics—which I’ll get to in the next section—modification of bases in RNA after its transcription leads to epitranscriptomics. This somewhat of a tongue-twister term was first introduced in 2013 by Sibbritt et al. in reference to increasing amounts of data for methylated bases in mRNA in the form of N6-methyladenosine (m6A) and 5-methylcytosine (m5C).

Both m6A and m5C have long been known to exist in both prokaryotic and eukaryotic organisms, but only more recently have a flurry of publications shed light—pun intended—on the precise locations, as well as enzymatic introduction and removal of m6A and m5C. This dynamic “writing” and “erasing” has been expertly reviewed by He and coworkers, who have also contributed to these discoveries.

m1A; taken from genengnews.com

m1A; taken from genengnews.com

He and collaborators at the University of Chicago, together with researchers in Israel, have recently reported in venerable Nature magazine a new mRNA modification, namely N1-methyladenosine (m1A), which occurs on thousands of different gene transcripts in eukaryotic cells spanning genetically simple yeast to much more complex mammals.

Taking advantage of newly developed sequencing approaches—i.e. brighter lamp posts in my metaphor—they showed that m1A is enriched around the start codon upstream of the first splice site. More specifically, they observed that m1A “preferentially decorates more structured regions around canonical and alternative translation initiation sites, is dynamic in response to physiological conditions, and correlates positively with protein production.”

They conclude by noting that “these unique features are highly conserved in mouse and human cells, strongly indicating a functional role for m1A in promoting translation of methylated mRNA.” So, as I said at the beginning of this blog, seek and ye shall find, and He did—capital H and pun intended.

Incidentally, those of you who are chemists will recognize that the ionic structure for m1A pictured above can undergo deprotonation to form a formally neutral counterpart having an H-N=C-N-CH3 moiety, as shown in TriLink’s catalog for the triphosphate derivative of m1A. Which one, or the proportion of these two structures for m1A exists in an mRNA of interest will depend on sequence context, local pH, etc. In this regard, scientists will need to somehow seek, in order to find, those answers in epitranscriptomics.

Expanding Epigenetics

m1A; taken from genengnews.com

m1A; taken from genengnews.com

Until recently, mammalian epigenetics had been solely focused on 5-methyl-2’-deoxycytidine and sequentially oxidized versions thereof, i.e. having hydroxyl, formyl, and carboxyl moieties, all of which are offered by TriLink as various products as either 5’-triphosphates or oligonucleotides. In less complex, prokaryotic organisms such as bacteria, N6-methyl-2’-deoxyadenosine (m6dA) is prevalent, but whether it is found in mammals has remained unclear until now.

A multi-university collaboration with the single-molecule-sequencing company Pacific Biosciences now report (Wu et al. 2016) the existence of m6dA in mouse stem cells. This landmark discovery was even more exciting because of the identification of an enzyme that removes methyl groups from m6dA, and by finding that m6dA is enriched in certain regulatory DNA sequences. Together these data provide clues to the possible function of m6dA in mammalian genomes.

Akin to my introductory light-from-the-lamp-post metaphor, detection and location of m6dA was enabled by more powerful analytical methods compared to those available in the past. Using state-of-the-art liquid chromatography-tandem mass spectrometry (LC-MS/MS), Wu et al. found that m6dA represented only 6–7 bases per million (!) adenines genome-wide. m6dA was enriched ~4-fold in genomic regions associated with a rare histone protein, H2AX, although the reasons for this association remain unclear.

The authors next determined specific locations of m6dA in sequences of DNA bound to H2AX by using Pacific Biosystems single-molecule real-time (SMRT) sequencing, which detects different kinetics with which a polymerase enzyme replicates modified bases compared with standard ones. Readers interested in this clever—dare I say “SMaRT”—method can check out my previous blog on SMRT.

In my opinion, the most challenging aspect of investigating epigenetics and epitranscriptomics is deciphering the dynamics and functional impact of “writing” and “erasing” methyl groups on bases in DNA and RNA, respectively. Erasure, i.e. removal of methyl groups is carried out by so-called demethylase enzymes. Several demethylases of the AlkB protein family have been shown to remove methyl groups from m6A in RNA as a means of regulating mRNA function. In mammals, this protein family has nine members, among which AlkBH1-deficiency was found by Wu et al. in mouse embryonic stem cells (ESCs) to lead to accumulation of m6dA in the genome, and that AlkBH1 could remove methyl groups from m6dA in DNA in vitro.

Intriguingly, Wu et al. further discovered that AlkBH1 worked most effectively on single-stranded DNA in vitro, thus raising the question of whether the enzyme preferentially operates during transcription or DNA replication in vivo, when DNA is transiently single stranded.

It’s also worth noting that enzymes that “write” (i.e. add) methyl groups to the N6-position of dA in mammalian DNA remain to be defined, as do the “reader” proteins that detect genomic m6dA.

In conclusion, I hope that this brief synopsis of new findings in “epi-marking” RNA and DNA has been illuminating—pun intended—with regard to molecular biology and the need for applying ever more powerful analytical methods to find more of what we are looking for: the molecular basis for living organisms.

On second thought, it seems to me that scientific discovery is perhaps more like moving forward from one lighted area to the next…

As usual, I welcome your comments.

Highlights of 2015 Publications Using TriLink BioTechnologies Products

  • Publications Citing TriLink Products Exceed 6,000
  • TriLink Products Showed up at a Rate of One Publication per Work Day
  • Among These Customer Publications, Modified mRNA is Trending
Taken from thetrymovement.com

Taken from thetrymovement.com

From my college classes decades ago, I can still clearly recall—thankfully—many “ah ha” moments. Most importantly is when I crystalized to purity and then confirmed structure by NMR the first compound I synthesized in Organic Chemistry Lab. Another ah ha moment—but on a completely different level—was during a philosophy class when the professor partially paraphrased a quote by Aristotle as “we are what we do.” The full quote given above is even more thought provoking because it ties in the notion of excellence, which I took to heart then, and have attempted to live by ever since.

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Longing for Longevity

  • Craig Venter’s HGI is Slow Moving Compared to Google’s Calico
  • 90 is the New 40: Palo Alto Longevity Prize
  • A 1,000 Year-old Human has Already Been Born, Says Aubrey de Grey
  • Dosing with Modified mRNA for Telomerase Turns Back the Clock—Sort Of

I suspect that thinking about immortality—if not living longer—was something humans mused about ever since they comprehended the notion of death. Why we die and—more importantly—seeking ways to avoid death inevitably followed. Among ancient legends about immortality, I’m fond of alchemists searching for the Philosopher’s Stone (aka elixir of life), although that is predated by several millennia of other mythical attempts by ancient Egyptians, Chinese and Greeks to live forever. Forever is a long time, you may be thinking, and perhaps overreaching even conceptually (although that’s been debated), so how about the likelihood of living a lot longer? If you’re skeptical about living longer and—here’s the catch—enjoying it—here are some scientifically notable folks who think this isn’t too far from reality.

"The Alchymist [sic] in Search of the Philosopher's Stone" painted by Joseph Wright in 1771. Taken from ultraculture.org.

“The Alchymist [sic] in Search of the Philosopher’s Stone” painted by Joseph Wright in 1771. Taken from ultraculture.org.

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