A human putative lymphocyte G0/G1 switch gene containing a CpG-rich island encodes a small basic protein with the potential to be phosphorylated.
Genes actively involved in the G0/G1 switch (G0S genes) may be differentially expressed during the lectin-induced switch of lymphocytes from the G0 to the G1 phases of the cell cycle. This paper presents studies of G0S2, a member of a set of putative G0S genes, for which cDNAs were cloned and selected on the basis of differential cDNA hybridization. G0S2 mRNA increases transiently within 1-2 hr of the addition of lectin or cycloheximide to cultured blood mononuclear cells. Comparison of a nearly full-length cDNA sequence with the corresponding genomic sequence reveals one small intron and an open reading frame in the second exon. The derived 103-amino-acid basic protein has two potential alpha-helical domains separated by a hydrophobic region with the potential to generate turns and assume a beta-sheet conformation. Consistent with involvement in the G0/G1 switch, the protein contains potential sites for phosphorylation by protein kinase C and casein kinase II. The gene contains a CpG-rich island suggesting expression in the germ line. An upstream segment contains tandem dinucleotide repeats (CT)19/(CA)16. There is a suitably located TATA box, but potential sites for CCAAT-box binding factors are far upstream, embedded in a 42-nucleotide repeat element. Potential sites for transcription factors AP1, AP2, and AP3 are consistent with rapid transcriptional activation in response to inducing agents.
Russell
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Department of Biochemistry, Queen's University, Kingston, Ontario, Canada.
Forsdyke
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D000595:Amino Acid Sequence; D001483:Base Sequence; D001798:Blood Proteins / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics; D015226:Dinucleoside Phosphates / Q000032:analysis*; D005091:Exons; D005812:Genes, Switch; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007438:Introns; D008214:Lymphocytes / Q000737:chemistry*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011487:Protein Conformation; D012333:RNA, Messenger / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D016385:TATA Box; D014157:Transcription Factors / Q000378:metabolism
D001798:Blood Proteins; D004247:DNA; D015226:Dinucleoside Phosphates; D012333:RNA, Messenger; D014157:Transcription Factors; C015772:CpG dinucleotide