71.67 T lymphocyte activation is accompanied by the down-regulation of three G alpha genes.
A direct role for heterotrimeric G proteins in signal transduction through the T cell receptor complex has been hypothesized, but never definitively demonstrated. Nonetheless, several lines of evidence support the importance of G proteins in lymphocyte activation and differentiation events. In this study, PCR was used to generate cDNA segments of murine G alpha genes from a lymphocyte cell line by amplifying areas of divergent sequence between conserved primer sites. These murine cDNAs are homologous with previously reported G alpha s, G alpha i2, and G alpha i3 genes from other tissues and were used as probes to determine their levels of mRNA expression in a mitogen- and antigen-stimulated T lymphocyte line, 71.67, which provides a model for T cell activation. mRNA levels for all three G alpha genes were found to be differentially down-regulated with 71.67 activation, but not with stimulation of three more immature lymphocyte cell lines. These findings suggest that an important element in signal transduction through these G proteins in lymphocytes may include regulation of G alpha mRNA steady-state levels.
Rock
B
B
Department of Dermatology, Emory University, Atlanta, Georgia 30322, USA.
Xin
L
L
Niederhuber
J E
JE
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers / Q000737:chemistry; D015536:Down-Regulation; D019204:GTP-Binding Proteins / Q000235:genetics*; D015870:Gene Expression; D005796:Genes; D008213:Lymphocyte Activation; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction
D017931:DNA Primers; D012333:RNA, Messenger; D019204:GTP-Binding Proteins