Modification of T cell receptor beta chain gene: the J2 region but not the J1 region of the T cell receptor beta chain gene is hypomethylated in human B cells and monocytes.
In order to determine the relationship between the generation of a 1.0 kb mRNA and methylation of the T cell receptor beta chain gene, we have analyzed the methylation state of the T cell receptor beta chain gene (T beta) in monocyte and B cell DNA, focusing on the J1 and J2 regions of this gene in human genomic DNA. We have observed that a portion of the J2 region of T beta rich with CpG sequences is nonmethylated in both monocyte and B cell DNA but that the J1 region is methylated in both cell DNAs. We suggest that the hypomethylation of the J2 region constitutes a condition in which a 1.0 kb truncated mRNA of the beta chain gene is expressed in B cells. We have also found that the CpG sequence 1.0 kb 3' to the last exon of the J2 was totally nonmethylated in B cell DNA but methylated in half of monocyte DNA. This difference in methylation between monocyte and B cell DNA may reflect the differential transcriptional activity in monocytes and B cells of a 1.0 kb mRNA of T beta.
Sakamoto
S
S
Laboratory of Molecular Immunoregulation, National Cancer Institute, Frederick, MD 21701-1013.
Young
H A
HA
D001402:B-Lymphocytes / Q000502:physiology*; D002874:Chromosome Mapping; D004262:DNA Restriction Enzymes; D005786:Gene Expression Regulation; D006801:Humans; D008745:Methylation; D009000:Monocytes / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D016693:Receptors, Antigen, T-Cell, alpha-beta
D012333:RNA, Messenger; D011948:Receptors, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta; D004262:DNA Restriction Enzymes