In a paper published online in advance in Nature this week, an international team led by investigators at Umeå University in Sweden describes a "novel pathway of small guide RNA maturation and the first example of a host factor — RNase III — required for bacterial RNA-mediated immunity against invaders." Using RNA-seq on Streptococcus pyrogenes, the team identified a "trans-encoded small RNA with 24-nucleotide complementarity to the repeat regions of crRNA precursor transcripts" — a tracrRNA — which the team says guides the maturation of crRNAs via RNase III and the CRISPR-associated Csn1 protein.
Researchers at Ohio State University describe in Nature this week "the complete biosynthesis of the genetically encoded amino acid pyrrolysine from lysine." Pyrrolysine, which is "necessary for all of the known pathways by which methane is formed from methylamines5, 6," is biosynthesized through a series of intermediates, the authors write, adding that lysine is its sole precursor. The Ohio State team suggests that the pathway intermediates they found "may provide new avenues by which the pyl system can be exploited to produce recombinant proteins with useful modified residues."
In an advance online publication appearing in Nature Genetics this week, researchers in Japan show that a common variant at GPC5, which encodes glypican-5, is associated with acquired nephrotic syndrome, a disease characterized in part by dysfunction of glomerular epithelial cells. In a genome-wide association study, and in subsequent gene expression analyses in a mouse model, the team validates GPC5 as a susceptibility gene for nephritic syndrome. The authors suggest that the gene could be a "promising therapeutic target for reducing podocyte [glomerular epithelial cell] vulnerability in glomerular disease."
A trio of investigators at Columbia University this week reports in Nature Structural and Molecular Biology that "long telomeres are preferentially extended during recombination-mediated telomere maintenance." More specifically, the team studied recombination-mediated telomere extension events in Saccharomyces cerevisiae lacking telomerase, in which observed the preferential extension of long telomeres. As a result of their investigation in yeast, the researchers "speculate that telomere length may be important in determining whether cancer cells use telomerase or ALT [alternative lengthening of telomeres] to bypass replicative senescence."