In a paper published online in advance in Cell this week, investigators at the University of Vienna and the Hebrew University-Hadassah Medical School show that the toxin MazF "cleaves at ACA sites at or closely upstream of the AUG start codon of some specific mRNAs and thereby generates leaderless mRNAs." The team also reports on a subpopulation of ribosomes that it says "selectively translates the described leaderless mRNAs both in vivo and in vitro."
In another Cell paper published online in advance this week, researchers at the University of Toronto and elsewhere describe what they call "an evolutionarily conserved embryonic stem cell-specific AS [alternative splicing] event that changes the DNA-binding preference of the forkhead family transcription factor FOXP1." The team shows than an ESC-specific isoform of FOXP1 "stimulates the expression of transcription factor genes required for pluripotency ... while concomitantly repressing genes required for ESC differentiation," and that it also "contributes to efficient reprogramming of somatic cells into induced pluripotent stem cells."
Over in the special issue of Molecular Cell dedicated the regulatory RNAs, researchers at the University of Arizona and Case Western Reserve University show that Ded1 — of the conserved Ded1/DDX3 DEAD-box protein — "interacts directly with eIF4G to promote formation of a pre-translation complex," and that it can either repress or promote translation, "depending in ATPase activity."
In the same issue, investigators at the University of California, Riverside, show that "the long, non-coding RNA Mira mediates recruitment of MLL1 to chromatin in mouse embryonic stem cells." They show that the gene for this lncRNA is in the spacer DNA region that separates Hoxa6 and Hoxa7, and that it is activated by retinoic acid. Overall, the authors say that their study connects Mira to "the recruitment of MLL1 to target genes and implicate lncRNAs in epigenetic activation of gene expression during vertebrate cell-fate determination."