Newly discovered rare code of life: another set of codes for genetic reading

New research suggests that the brain and testes appear to be well-adapted to use many different kinds of genetic code to produce specific protei.

Rare fragments of genetic code may be another way to control cellular machine.

In fact, both fruit fly and human testes appear to be enriched in the protein products of these rarely used segments of the genetic co.

Ten years after working out that the structure of DNA is a double helix consisting of the bases A, C, T and G, Francis Crick went on to decode the intermediate steps, in which the three letters are translated into a "codon",.

Shocking but still confusing at the time, this layer of the code for life used 61 different three-letter codons, yielding only 20 amino acids, meaning that many codons were used to describe the same thi.

"We learned in biology class that amino acids don't change when you switch from one codon to another, which is called a silent mutati.

"However, when the researchers sequenced all these different organisms, they found a hierarchy," Fox sa.

A translucent Drosophila larva emits green fluorescent protein (GFP), which is expressed by a rare codon in the Drosophila geno.

Fox wondered whether the rarity played a role in the function of liver cells and bone cel.

Fox and his team, led by doctoral student Scott Allen, wanted to amplify the rare codon, using their favorite model fruit fly, the laboratory fruit f.

Fox was working with colleague Christopher Contor, the George Barth Geller Distinguished Professor of Pharmacology at Duke University, on a gene called KRAS, which carries many rare codons, especially Plays an adverse role in pancreatic canc.

"It turns out that the KRAS gene is designed in a way that it should be difficult to make either," Fox sa.

Fox's team developed a new method for analyzing tissue-specific codon usage to see where and how codons that are rare in Drosophila are us.

"From this cancer collaboration, I realized we could take similar approaches and apply them to my main research question, how do tissues know what they are," Fox sa.

In further experiments, they found that fruit fly testes -- and human testes -- were more tolerant of codon diversity, but fruit fly ovaries were n.

A particular gene with a large number of rare codons, RpL10Aa, was evolutionarily updated to help build ribosomes, the protein assembly machinery within cel.

"The testis seems to allow almost any gene expression in a way that could make it a breeding ground for new genes, if you will," Fox sa.

"The testis seems to be where the young genes are expressed fir.

So we think it's a more permissive tissue that allows new genes to take ro.

"

"We think that what we're seeing is that rare codons are a way to limit the activity of young genes in the testis during this evolutionary process," Fox sa.

"This will enable rare codons to be another layer of control and fine-tuning in gen.

"

"This work opens new frontiers in identifying codon usage as the basis for tissue-specific gene expression in animals," said the eLife edito.

references:

“Distinct responses to rare codons in select Drosophila tissues” by Scott R Allen, Rebeccah K Stewart, Michael Rogers, Ivan Jimenez Ruiz, Erez Cohen, Alain Laederach, Christopher M Counter, Jessica K Sawyer, Donald T Fox, 6 May 2022, eLif.

DOI: 17554/eLi.

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