p16 INK4a gene promoter variation and differential binding of a repressor, the ras-responsive zinc-finger transcription factor, RREB.
BALB/c mice are susceptible to the development of pristane-induced plasma cell tumors, and have a rare allelic variant in the coding region of the p16(INK4a) (p16) tumor suppressor gene that produces a protein with impaired activity. We have now found that the BALB/c p16 promoter has an allelic variant that may also compromise p16 activity. Following pristane treatment, BALB/c p16 mRNA levels in B cells were lower than that in DBA/2 or C.D2-Pctr1, a resistant BALB/c congenic strain that harbors DBA/2 chromatin surrounding the p16 locus. Four sequence variants were found between BALB/c and DBA/2 in the p16 promoter region. In reporter assays, the DBA promoter was at least four times more active in driving luciferase expression than the BALB/c promoter. Most of the difference in activity was localized to a single nucleotide deletion in BALB/c. This deletion created a consensus binding site for RREB, a ras-responsive transcriptional element with zinc-finger binding motifs. Transient transfections with RREB confirmed that the p16 promoter can be downregulated by RREB, in a Ras- or Mek-dependent manner, and that the BALB/c promoter is more sensitive than DBA/2 to regulation by RREB. BALB/c mice have both regulatory and coding region defects that may contribute to the impairment of p16 gene function.
Zhang
Shuling
S
Laboratory of Genetics, Center for Cancer Research, Bethesda, MD 20892-4255, USA.
Qian
Xiaolan
X
Redman
Chanelle
C
Bliskovski
Valeri
V
Ramsay
Edward S
ES
Lowy
Douglas R
DR
Mock
Beverly A
BA
D016475:3T3 Cells; D000483:Alleles; D000818:Animals; D020296:Animals, Congenic; D001402:B-Lymphocytes / Q000378:metabolism; D001665:Binding Sites; D016384:Consensus Sequence; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D017930:Genes, Reporter; D019942:Genes, p16; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D048369:MAP Kinase Kinase 1; D051379:Mice; D008807:Mice, Inbred BALB C / Q000235:genetics*; D008811:Mice, Inbred DBA / Q000235:genetics*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000502:physiology; D010954:Plasmacytoma / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D013045:Species Specificity; D013154:Spleen / Q000378:metabolism; D013729:Terpenes / Q000494:pharmacology; D014157:Transcription Factors / Q000502:physiology*; D014162:Transfection; D018631:ras Proteins / Q000502:physiology
D004268:DNA-Binding Proteins; D012333:RNA, Messenger; C101743:RREB1 protein, human; D011993:Recombinant Fusion Proteins; D013729:Terpenes; D014157:Transcription Factors; C009042:pristane; D008156:Luciferases; D017346:Protein Serine-Threonine Kinases; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; C482127:Map2k1 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases; D018631:ras Proteins