tailieunhanh - Báo cáo y học: "RNA interference has a role in regulating Drosophila telomeres"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Minireview cung cấp cho các bạn kiến thức về ngành y đề tài: RNA interference has a role in regulating Drosophila telomeres. | Minireview RNA interference has a role in regulating Drosophila telomeres Elena Casacuberta and Mary-Lou Pardue Addresses ICREA IBMB-CSIC and fIRB Parc Cientific de Barcelona Josep Samitier 1-5 Barcelona 08028 Spain. Department of Biology Massachusetts Institute of Technology Cambridge MA 02139 USA. Correspondence Mary-Lou Pardue. Email mlpardue@ Published 31 May 2006 Genome Biology 2006 7 220 doi gb-2006-7-5-220 The electronic version of this article is the complete one and can be found online at http 2006 7 5 220 2006 BioMed Central Ltd Abstract Unlike many other organisms Drosophila maintains its telomeres by the transposition of retrotransposons to chromosome ends. Recent work shows that proteins in the RNA interference pathway specifically regulate the expression of these retrotransposons and frequency of transposition in germline cells but do not affect retrotransposon expression or telomere function in the soma. At first glance the telomeres of the fruit fly Drosophila melanogaster seem very different from those of other organisms. At a second glance however the difference is mostly in the size and sequence of the DNA repeats that make up the telomeres. Unlike the simple sequence telomere repeats of most eukaryotes the Drosophila repeats are made of telomere-specific transposable elements and are three orders of magnitude larger than the repeats found in most eukaryotes 6-12 kb versus 5-9 bp Figure 1 . The Drosophila telomere elements are non-LTR retrotransposons which transpose by poly A RNA that is reverse transcribed directly onto the chromosome. Thus successive transpositions onto the end of the chromosome extend the telomere as do the simple repeats added by telomerase in other organisms. Nevertheless both telomerase-associated repeats and retrotransposons appear to serve the same functions in the biology of the cell 1 - such as maintaining the length of chromosome ends distinguishing true ends from breaks in DNA .