Src-homology domain 2 is responsible for transcriptional suppression induced by expression of Lck.
Overexpression of Lck was shown, by our previous study, to suppress gene transcription from various viral and cellular promoters. The suppression of transcription from human T-cell leukemia virus promoter by Lck was independent of the presence of the enhancer core sequences within the long terminal repeat. The suppression of transcription was observed with Lck mutants that had either diminished or enhanced tyrosine-kinase activity. A mutant lacking the myristylation site also suppressed transcription. From the analysis with various deletion mutants of Lck, it was suggested that Src-homology domain 2 (SH2) is both necessary and sufficient for the suppression of transcription. A similar effect was also observed with the SH2 domain of the v-src gene. Thus, overexpression of Lck could suppress gene expression through a unique function of the SH2 domain.
Ohta
M
M
Virology Division, National Cancer Center Research Institute, Tokyo, Japan.
Nagai
H
H
Nyunoya
H
H
Shimotohno
K
K
D000595:Amino Acid Sequence; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics*; D051858:Forkhead Transcription Factors; D017930:Genes, Reporter; D006801:Humans; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010766:Phosphorylation; D017384:Sequence Deletion; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics*; D014162:Transfection; D018909:src Homology Domains / Q000235:genetics* / Q000502:physiology; D019061:src-Family Kinases / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; C075814:FOXN2 protein, human; D051858:Forkhead Transcription Factors; D014157:Transcription Factors; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D019061:src-Family Kinases