Effect of deletion of the DNase I hypersensitive sites on the transcription of chicken Ig-beta gene and on the maintenance of active chromatin state in the Ig-beta locus.
The role of DNase I hypersensitive sites (DHSs) in transcription of the B cell-specific Ig-beta gene and in maintenance of active chromatin state in the Ig-beta 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-beta promoter and its upstream Na channelgene, resulted in the absence of Ig-beta mRNA. Three regions except the region in the Na channel gene were involved in the transcription of Ig-beta 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-beta 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-beta promoter and at DT40-specific DHSs was observed in cells in which DHSs between the Na channel gene and Ig-beta promoter were deleted; therefore, these DHSs are prerequisite for transcription of the Ig-beta gene but not required for the maintenance of active chromatin state in the Ig-beta locus. Thus, epigenetic factors required for the maintenance of the active chromatin state are suggested to reside in other regions than those deleted in this study.
Matsudo
Hiroki
H
Department of Life Science, and Frontier Project Life's Adaptation Strategies to Environmental Changes, Rikkyo University, College of Science, Toshima-ku, Tokyo 171-8501, Japan.
Osano
Kyoichi
K
Arakawa
Hiroshi
H
Ono
Masao
M
D000107:Acetylation; D000818:Animals; D015703:Antigens, CD / Q000235:genetics*; D051925:CD79 Antigens; D002645:Chickens; D002843:Chromatin / Q000378:metabolism*; D002874:Chromosome Mapping; D003850:Deoxyribonuclease I / Q000378:metabolism*; D013006:Growth Hormone / Q000235:genetics; D006657:Histones / Q000378:metabolism; D014158:Transcription, Genetic
D015703:Antigens, CD; D051925:CD79 Antigens; D002843:Chromatin; D006657:Histones; D013006:Growth Hormone; D003850:Deoxyribonuclease I