Scientists uncover dual-function messenger RNA

ASU scientists discover dual-function messenger RNA
The central dogma of molecular biology displaying what is occurring on this examine. Credit score: Julian Chen

For the very first time, a examine led by Julian Chen and his group in Arizona State College’s College of Molecular Sciences and the Biodesign Institute’s Middle for the Mechanism of Evolution, has found an unprecedented pathway producing telomerase RNA from a protein-coding messenger RNA (mRNA).

The central dogma of molecular biology specifies the order through which genetic info is transferred from DNA to make proteins. Messenger RNA molecules carry the genetic info from the DNA within the nucleus of the cell to the cytoplasm the place the proteins are made. Messenger RNA acts because the messenger to construct proteins.

“Truly, there are various RNAs (ribonucleic acids) that aren’t used to make proteins,” defined Chen. “About 70 % of the human genome is used to make noncoding RNAs that do not code for protein sequences however produce other makes use of.”

Telomerase RNA is without doubt one of the noncoding RNAs that assembles together with telomerase proteins to type the enzyme telomerase. Telomerase is essential for mobile immortality in most cancers and stem cells. On this examine, Chen’s group exhibits {that a} fungal telomerase RNA is processed from a protein-coding mRNA, as an alternative of being synthesized independently.

“Our discovering from this paper is paradigm-shifting. Most RNA molecules are synthesized independently and right here we uncovered a twin operate mRNA that can be utilized to supply a protein or to make a noncoding telomerase RNA, which is basically distinctive,” stated Chen. “We might want to do much more analysis to grasp the underlying mechanism of such an uncommon RNA biogenesis pathway.”

Fundamental analysis on the metabolism and regulation of mRNA has led to necessary medical functions. For instance, a number of COVID-19 vaccines use messenger RNA as a method to supply viral spike proteins. In these vaccines, the mRNA molecules are ultimately degraded after which absorbed by our our bodies.

This new strategy has benefits over DNA vaccines which run the potential danger of being deleteriously and completely integrated into our DNA. The invention of dual-function mRNA biogenesis on this work would possibly result in progressive methods of constructing future mRNA vaccines.

On this examine Chen’s group found the sudden mRNA-derived telomerase RNA within the mannequin fungal organism Ustilago maydis or corn smut. Corn smut, additionally known as Mexican truffle, is edible and provides a scrumptious umami impact to many dishes, for instance tamales and tacos. The examine of RNA and telomere biology in corn smut could present alternatives for locating novel mechanisms for mRNA metabolism and telomerase biogenesis.

Why examine telomerase RNA?

The Nobel Prize in Physiology or Medication was awarded in 2009 “for the invention of how chromosomes are protected by telomeres and the enzyme telomerase.” Telomerase was first remoted from a unicellular organism residing in pond scum. Because it later turned out, telomerase exists in virtually all eukaryotic organisms, together with people, and performs an important function in growing older and most cancers. Scientists have been scrambling to find methods to make the most of telomerase to make human cells immortal.

Typical human cells are mortal and can’t perpetually renew themselves. As demonstrated by Leonard Hayflick a half-century in the past, human cells have a restricted replicative life span, with older cells reaching this restrict earlier than youthful cells. This “Hayflick restrict” of mobile life span is straight associated to the variety of distinctive DNA repeats discovered on the ends of the genetic material-bearing chromosomes. These DNA repeats are a part of the protecting capping constructions, termed “telomeres,” which safeguard the ends of chromosomes from undesirable and unwarranted DNA rearrangements that destabilize the genome.

Every time the cell divides, the telomeric DNA shrinks and can ultimately fail to safe the chromosome ends. This steady discount of telomere size features as a “molecular clock” that counts right down to the tip of cell progress.

The diminished potential for cells to develop is strongly related to the growing older course of, with the diminished cell inhabitants straight contributing to weak point, sickness and organ failure.

Counteracting the telomere shrinking course of is telomerase, the enzyme that uniquely holds the important thing to delaying and even reversing the mobile growing older course of. Telomerase offsets mobile growing older by lengthening the telomeres, including again misplaced DNA repeats so as to add time onto the molecular clock countdown, successfully extending the life span of the cell.

Telomerase lengthens telomeres by repeatedly synthesizing very brief DNA repeats of six nucleotides—the constructing blocks of DNA—with the sequence “GGTTAG” onto the chromosome ends from a template positioned throughout the RNA part of the enzyme itself.

The gradual shrinking of telomeres negatively impacts the replicative capability of human stem cells, the cells that restore broken tissues and/or replenish growing older organs in our our bodies. The exercise of telomerase in grownup stem cells merely slows down the countdown of the molecular clock and doesn’t fully immortalize these cells. Subsequently, grownup stem cells turn out to be exhausted in aged people as a consequence of telomere size shortening which leads to elevated therapeutic instances and organ tissue degradation from insufficient cell populations.

Tapping the total potential of telomerase

Understanding the regulation and limitation of the telomerase enzyme holds the promise of reversing telomere shortening and mobile growing older with the potential to increase human life span and enhance wellness of aged people.

Human ailments that embrace dyskeratosis congenita, aplastic anemia and idiopathic pulmonary fibrosis have been genetically linked to mutations that negatively have an effect on telomerase exercise and/or speed up the lack of telomere size. This accelerated telomere shortening carefully resembles untimely growing older with elevated organ deterioration and a shortened affected person life span attributable to critically inadequate stem cell populations. Rising telomerase exercise is seemingly probably the most promising technique of treating these genetic ailments.

Whereas elevated telomerase exercise might deliver youth to growing older cells and remedy untimely aging-like ailments, an excessive amount of of a great factor could be damaging for the person. Simply as youthful stem cells use telomerase to offset telomere size loss, most cancers cells make use of telomerase to take care of their aberrant and damaging progress. Augmenting and regulating telomerase operate should be carried out with precision, strolling a slender line between cell rejuvenation and a heightened danger for most cancers growth.

Distinct from human stem cells, somatic cells represent the overwhelming majority of the cells within the human physique and lack telomerase exercise. The telomerase deficiency of human somatic cells reduces the danger of most cancers growth, as telomerase fuels uncontrolled most cancers cell progress. Subsequently, medicine that improve telomerase exercise indiscriminately in all cell sorts are usually not desired. Small molecule medicine could be screened or designed to extend telomerase exercise solely inside stem cells for illness therapy in addition to antiaging therapies with out growing the danger of most cancers.

The examine of telomerase RNA biogenesis in corn smut could unveil new mechanisms for telomerase regulation and provide new instructions on the right way to modulate or engineer human telomerase for improvements in creating antiaging and anticancer therapeutics.

This examine, “Biogenesis of telomerase RNA from a protein-coding mRNA precursor,” was simply revealed within the Proceedings of the Nationwide Academy of Sciences. The ASU group contains first authors postdoc Dhenugen Logeswaran and former analysis assistant professor Yang Li, doctoral pupil Khadiza Akhter, former postdoc Joshua Podlevsky (at present at Sandia Nationwide Labs, Albuquerque, New Mexico) and two undergraduate college students Tamara Olson and Katherine Fosberg.

Chen additionally commented on the caliber of the ASU undergraduate college students, Tamara Olson and Katherine Fosberg, who had been working in his lab for over a 12 months. “They spent loads of time within the lab and had been absolutely concerned in our analysis.”

What lobsters can train us about immortality

Extra info:
Logeswaran, Dhenugen et al, Biogenesis of telomerase RNA from a protein-coding mRNA precursor, Proceedings of the Nationwide Academy of Sciences (2022). DOI: 10.1073/pnas.2204636119.

Scientists uncover dual-function messenger RNA (2022, October 3)
retrieved 4 October 2022

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