tailieunhanh - Báo cáo sinh học: "Insulators as mediators of intra- and inter-chromosomal interactions: a common evolutionary theme"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Insulators as mediators of intra- and inter-chromosomal interactions: a common evolutionary theme. | Journal of Biology Minireview Insulators as mediators of intra- and inter-chromosomal interactions a common evolutionary theme Chin-Tong Ong and Victor G Corces Address Department of Biology Emory University 1510 Clifton Road NE Atlanta GA 30322 USA. Correspondence Victor G Corces. Email vcorces@ Abstract Insulator elements mediate intra- and inter-chromosomal interactions. The insulator protein CCCTC-binding factor CTCF is important for insulator function in several animals but a report in BMC Molecular Biology shows that Caenorhabditis elegans yeast and plants lack CTCF. Alternative proteins may have a similar function in these organisms. Eukaryotic genomes have developed a variety of strategies for efficiently orchestrating the complex patterns of gene expression required for proper cellular differentiation. Comparative genome analyses suggest that developmental evolution is largely driven by the increase in the complexity of these expression patterns 1 . Consistent with this hypothesis recent studies indicate that transcription factorcoding genes tend to be under greater positive evolutionary selection compared with other genes 2 . To establish and maintain cell-specific patterns of gene expression regions of the genome are kept in a silenced state while immediately adjacent regions are transcriptionally active because of the presence of promiscuous enhancer elements that can act over large distances. Insulators were originally described as DNA regulatory elements that ensure the progress of an accurate transcriptional program by keeping in check communication between enhancers and promoters and creating boundaries that prevent inappropriate interactions between adjacent chromatin domains. Accumulating evidence suggests that these properties of insulators arise from their ability to mediate intra- and inter-chromosomal interactions which result in the formation of chromatin loops through clustering of multiple insulator sites 3 . Depending on the .