tailieunhanh - Báo cáo sinh học: "Making the jump: new insights into the mechanism of trans-translation"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Making the jump: new insights into the mechanism of trans-translation. | Journal of Biology BioMed Central Minireview Making the jump new insights into the mechanism of trans-translation Jacek Wower Iwona K Wower and Christian Zwieb1 Addresses Department of Animal Sciences Auburn University Auburn AL 36849 USA. tDepartment of Molecular Biology University of Texas Health Science Center at Tyler 11937 US Highway 271 Tyler TX 75708 USA. Correspondence Christian Zwieb. Email zwieb@ Published 30 June 2008 Journal of Biology 2008 7 17 doi jbiol78 The electronic version of this article is the complete one and can be found online at http content 7 5 I7 2008 BioMed Central Ltd Abstract The transfer-messenger ribonucleoprotein tmRNP which is composed of RNA and a small protein small protein B SmpB recycles ribosomes that are stalled on broken mRNAs lacking stop codons and tags the partially translated proteins for degradation. Although it is not yet understood how the ribosome gets from the 3 end of the truncated message onto the messenger portion of the tmRNA to add the tag a recent study in BMC Biology has shed some light on this astonishing feat. Discovery and properties of transfer messenger RNA tmRNA was discovered in 1995 1 when Simpson and coworkers overexpressed a mouse cytokine in Escherichia coll and found truncated cytokine peptides each tagged at the carboxyl termini with the same 11-amino acid residue extension AANDENYALAA. This tag sequence turned out to be encoded in a small stable RNA that had been identified many years earlier as a 10S RNA of unknown function 2 . The 10S RNA is now known as transfer messenger RNA tmRNA . As its name implies tmRNA has features of both transfer RNA and messenger RNA. One domain of the molecule known as the transfer RNA-like domain TLD has an amino acid acceptor stem chargeable with alanine and a T arm with modified nucleotides just as in tRNA Figure 1 . However the D arm of the tRNA-like domain is degenerated and there is no anticodon loop. A second domain the mRNA-like .