Apoptosis is induced in BHK cells by the tsBN462/13 mutation in the CCG1/TAFII250 subunit of the TFIID basal transcription factor.
A temperature-sensitive (ts) mutant of the BHK21 cell line derived from golden hamsters, tsBN462 has a mutation in the gene encoding the largest subunit of the TFIID complex, TAFII250/p230/CCG1, and arrests in the G1 phase at the nonpermissive temperature, 39.5 degrees C. We found that tsBN462 cells underwent apoptosis following growth arrest at 39.5 degrees C, suggesting a role for CCG1 as a repressor of apoptosis. By electron microscopic observation, tsBN462 cells at 39.5 degrees C showed characteristic features of apoptosis. Apoptosis was not suppressed by expression of Bc1-2 or the adenovirus E1B 19 kDa protein. Cell death was suppressed completely by expression of wild-type CCG1 and partially by wild-type p53, a growth suppressor protein. Cell cycle arrest induced by p53 may help survival of tsBN462 cells at 39.5 degrees C. Apoptosis was accelerated in SV40 large T antigen-transformed tsBN462 cells at 39.5 degrees C where SV40 large T antigen formed a complex with p53, implying that the apoptosis of tsBN462 cells at 39.5 degrees C occurred in a p53-independent manner. Our results suggest that CCG1/TAFII250 is required for the expression of factors regulating apoptosis.
Sekiguchi
T
T
Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan.
Nakashima
T
T
Hayashida
T
T
Kuraoka
A
A
Hashimoto
S
S
Tsuchida
N
N
Shibata
Y
Y
Hunter
T
T
Nishimoto
T
T
D017501:Adenovirus E1B Proteins / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D002460:Cell Line; D006224:Cricetinae; D005786:Gene Expression Regulation; D006801:Humans; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
D017501:Adenovirus E1B Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53