A nuclear matrix attachment region upstream of the T cell receptor beta gene enhancer binds Cux/CDP and SATB1 and modulates enhancer-dependent reporter gene expression but not endogenous gene expression.
We have previously identified a DNase I-hypersensitive site in the T cell receptor beta locus, designated HS1, that is located 400 base pairs upstream of the transcriptional enhancer Ebeta and is induced during CD4(-)CD8(-) to CD4(+)CD8(+) thymocyte differentiation. Using electrophoretic mobility shift assays, we show that HS1 induction correlates with increased binding of two nuclear factors, Cux/CDP and SATB1, to a 170-base pair DNA sequence within HS1. Furthermore, we demonstrate that HS1 is a nuclear matrix attachment region, referred to as MARbeta. These findings demonstrate that an analogous organization of cis-regulatory elements in which a nuclear matrix attachment region is in close proximity to an enhancer is conserved in the immunoglobulin and T cell receptor loci. In addition, we show that MARbeta represses Ebeta-dependent reporter gene expression in transient transfection assays. However, the targeted deletion of MARbeta from the endogenous locus does not change T cell receptor beta gene transcription in developing T cells. These contrasting results suggest a potential pitfall of functional studies of nuclear matrix attachment regions outside of their natural chromosomal context.
Chattopadhyay
S
S
Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Whitehurst
C E
CE
Chen
J
J
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002454:Cell Differentiation; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D018398:Homeodomain Proteins; D006801:Humans; D036961:Matrix Attachment Region Binding Proteins; D051379:Mice; D015530:Nuclear Matrix / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D012097:Repressor Proteins / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism; D014157:Transcription Factors; D014158:Transcription, Genetic
C080632:CUX1 protein, human; C000624101:Cux1 protein, mouse; D017931:DNA Primers; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D036961:Matrix Attachment Region Binding Proteins; D009687:Nuclear Proteins; D016693:Receptors, Antigen, T-Cell, alpha-beta; D012097:Repressor Proteins; C076189:SATB1 protein, human; D014157:Transcription Factors