tailieunhanh - Báo cáo khoa học: Effect of deletion of the DNase I hypersensitive sites on the transcription of chicken Ig-b gene and on the maintenance of active chromatin state in the Ig-b locus

The role of DNase I hypersensitive sites (DHSs) in transcription of the B cell-specificIg-bgene and in maintenance of active chromatin state in the Ig-b locus were examined. A total of 10 DHSs were divided into four regions, and each region was deleted separately in chicken B lymphocyte-derived DT40 cells. Deletion of three DHSs located between theIg-bpro-moter and its upstreamNa channelgene, resulted in the absence of Ig-b mRNA. Three regions except the region in theNa channelgene were involved in the transcription of Ig-bgene. . | iFEBS Journal Effect of deletion of the DNase I hypersensitive sites on the transcription of chicken Ig-b gene and on the maintenance of active chromatin state in the Ig-b locus Hiroki Matsudo1 Kyoichi Osano1 Hiroshi Arakawa2 and Masao Ono1 1 Department of Life Science and Frontier Project Life s Adaptation Strategies to EnvironmentalChanges Rikkyo University College of Science Toshima-ku Tokyo Japan 2 GSF Institute for Molecular Radiobiology Neuherberg-Munich Germany Keywords chicken Ig-b gene DNase I hypersensitive sites DT40 histone acetylation transcription Correspondence M. Ono Department of Life Science College of Science Rikkyo University Toshima-ku Tokyo 171-8501 Japan Fax Tel 81 339852387 E-mail mono@ Received 11 September 2004 revised 3 November 2004 accepted 15 November 2004 doi The role of DNase I hypersensitive sites DHSs in transcription of the B cell-specific Ig-b gene and in maintenance of active chromatin state in the Ig-b locus were examined. A total of 10 DHSs were divided into four regions and each region was deleted separately in chicken B lymphocyte-derived DT40 cells. Deletion of three DHSs located between the Ig-b promoter and its upstream Na channel gene resulted in the absence of Ig-b mRNA. Three regions except the region in the Na channel gene were involved in the transcription of Ig-b gene. The enhancing activity of DHSs as determined by transient transfection assays did not always correlate with the effect of DHS deletion on the expression level of Ig-b mRNA. In each deletion cells contained the same DHSs as observed in the predeletion cells indicating that deleted DHSs did not participate in the maintenance of DT40-specific DHSs. Enhanced acetylation of H3 and H4 histones at the Ig-b promoter and at DT40-specific DHSs was observed in cells in which DHSs between the Na channel gene and Ig-b promoter were deleted therefore these DHSs are prerequisite for transcription of the Ig-b gene but not