In the PNAS Early Edition this week, researchers in Israel report that initiator-tRNA can function as a pre-mRNA splicing regulator. They show that alternative splicing events "induced by mutations in the translation initiation AUG codon can be suppressed by expressing initiator-tRNA constructs carrying anticodon mutations that compensate for the AUG mutations," and that their results suggest a novel role for initiator-tRNA as a splicing regulator, separate from its documented role in protein translation.
Investigators at the National Institute of Allergy and Infectious Diseases report their simultaneous analysis of vaccinia virus and host HeLa cell transcriptomes using deep RNA-sequencing in PNAS this week. "The high resolution permitted determination of the precise boundaries of many mRNAs including read-through transcripts and location of mRNA start sites and adjacent promoters," the authors write.
Research published online in advance in PNAS this week reports that "RNA polymerase complexes cooperate to relieve the nucelosomal barrier and evict histones." Specifically, researchers from the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School examined "the encounter between multiple complexes of RNA polymerase and a nucleosome was analyzed in vitro," and found that "closely spaced complexes of transcribing Pol II can induce displacement of all core histones along the gene."
A team of investigators from France discusses E. coli-induced DNA damage, and how it triggers genomic instability in mammalian cells. "E. coli strains of phylogenetic group B2 harbor a genomic island called 'pks' that codes for the production of a polyketide-peptide genotoxin, Colibactin," the authors write, which can induce a "transient DNA damage response followed by cell division with signs of incomplete DNA repair, leading to anaphase bridges and chromosome aberrations." The team suggests that "colon colonization with these E. coli strains harboring the pks island could contribute to the development of sporadic colorectal cancer."