Expression of the novel tumour suppressor p33(ING1)is independent of p53.
A recently cloned tumour suppressor candidate, p33ING1, has been shown in vitro to collaborate with p53 to execute growth arrest and apoptosis. However, it is unclear as to how the expression of ING1 is regulated in normal and stress conditions. Using a p53-knockout mouse model, we investigated if the expression of ING1 was dependent on p53. We found that there was no difference in ING1 mRNA and protein levels between p53+/+ and p53-/- murine organs. In addition, when normal human epithelial keratinocytes (NHEK) and a keratinocyte cell line, HaCaT, which lacks wild-type p53 function, were exposed to UVB irradiation, the expression levels of ING1 were elevated in both NHEK and HaCaT cells. It is interesting, however, that UVB irradiation did not induce ING1 expression in dermal fibroblasts isolated from p53+/+ and p53-/- mice. Based on our findings, we therefore conclude that the expression of ING1 is independent of p53 status. UV induction of ING1 in keratinocytes suggests that ING1 may play a role in cellular stress response and skin carcinogenesis.
Cheung
K J
KJ
Department of Medicine, Division of Dermatology, University of British Columbia, Vancouver, British Columbia, V6H 3Z6, Canada.
Bush
J A
JA
Jia
W
W
Li
G
G
D000818:Animals; D018797:Cell Cycle Proteins; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D005347:Fibroblasts; D015870:Gene Expression / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000528:radiation effects; D016147:Genes, Tumor Suppressor / Q000528:radiation effects; D016158:Genes, p53 / Q000528:radiation effects; D006801:Humans; D000076023:Inhibitor of Growth Protein 1; D047908:Intracellular Signaling Peptides and Proteins; D015603:Keratinocytes; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009687:Nuclear Proteins; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis* / Q000235:genetics; D025521:Tumor Suppressor Proteins; D014466:Ultraviolet Rays
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C501503:ING1 protein, human; C501505:Ing1 protein, mouse; D000076023:Inhibitor of Growth Protein 1; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D011506:Proteins; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins