Identification of sites for distinct DNA binding proteins including Oct-1 and Oct-2 in the Cr2 gene.
The murine Cr2 gene produces two distinct products in a variety of murine cell types. Both of these transcripts appear to initiate from the same position within the gene but vary from one another via an alternative splicing event within the coding exons. An analysis of those gene sequences that might control the cell specific expression of the Cr2 gene has identified a region of Cr2 5' of the transcription start site that is conserved in both the murine Cr2 and human CR2 genes. When this region was examined using the gel shift assay with nuclear extracts from cells expressing Cr2 (B cells) and those that do not (T cells and fibroblasts), at least four distinct proteins were identified that bound to at least three distinct sites. The DNA sequence recognized by two of these proteins is the octamer sequence recognized by a family of transcriptional regulators including the B cell specific Oct-2 protein. During an acute bacterial infection, the levels of Oct-2 and Cr2 mRNA are both depressed. This suggests that the Oct-2 protein directly controls the transcriptional activity of the Cr2 gene and that during such an infection, the levels of Ag receptors on B cells (Ig and complement receptors) are diminished.
Christensen
S M
SM
Department of Pathology, University of Utah School of Medicine, Salt Lake City 84132.
Martin
B K
BK
Tan
S S
SS
Weis
J H
JH
D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D016384:Consensus Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D051863:Host Cell Factor C1; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D050811:Octamer Transcription Factor-1; D050813:Octamer Transcription Factor-2; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics; D011951:Receptors, Complement / Q000235:genetics*; D017464:Receptors, Complement 3d; D012045:Regulatory Sequences, Nucleic Acid; D016415:Sequence Alignment; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D000944:Antigens, Differentiation, B-Lymphocyte; D004268:DNA-Binding Proteins; C497693:Hcfc1 protein, mouse; D051863:Host Cell Factor C1; D009687:Nuclear Proteins; D050811:Octamer Transcription Factor-1; D050813:Octamer Transcription Factor-2; D009838:Oligodeoxyribonucleotides; C494166:Pou2f1 protein, mouse; C489206:Pou2f2 protein, mouse; D012333:RNA, Messenger; D011951:Receptors, Complement; D017464:Receptors, Complement 3d; D014157:Transcription Factors