Transcriptional co-factor CDCA4 participates in the regulation of JUN oncogene expression.
CDCA4, a member of the TRIP-Br transcriptional co-factor family, has been shown to possess a unique role in regulating the transcriptional activities of p53 as well as E2F1 transcription factors. In this study, we aimed to identify a pivotal transcriptional target gene regulated by CDCA4, so we suppressed CDCA4 expression by CDCA4-specific short interference RNA (siRNA) in HeLa cells, and then performed a DNA microarray analysis. Among the identified genes, we focused on JUN, 14-3-3eta, and IL6ST (gp130) mRNAs which were up-regulated in CDCA4-specific siRNA-transfected cells compared to control siRNA-transfected cells. We confirmed that JUN, 14-3-3eta, and IL6ST proteins were up-regulated when cells were transfected with CDCA4-specific siRNA. 14-3-3eta and IL6ST protein levels were unchanged upon on transfection of cells with JUN-specific siRNA, indicating that 14-3-3eta and IL6ST genes are not a direct target of JUN. Serine 63 and 73 phosphorylation of JUN was unchanged when cells were transfected with CDCA4-specific siRNA. In addition, JUN-driven reporter activity was unaffected by CDCA4 co-transfection, suggesting that CDCA4 affects solely JUN mRNA expression. Finally, by preparing various JUN promoter reporter constructs, we minimized the JUN promoter sequence that was affected by CDCA4 co-expression. Together, these results add an important role of CDCA4 in the context of transcriptional regulation and cell fate determination through the JUN oncogene.
Department of Life Sciences, Graduate School of Agriculture, Meiji University, Kawasaki, Kanagawa, Japan.
Moe
M
Tategu
Hiroki
H
Nakagawa
Reiko
R
Hayashi
Kenichi
K
Yoshida
D018797:Cell Cycle Proteins / Q000378:metabolism*; D050687:E2F1 Transcription Factor / Q000378:metabolism; D020862:GC Rich Sequence; D005786:Gene Expression Regulation; D016758:Genes, jun / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
C515965:CDCA4 protein, human; D018797:Cell Cycle Proteins; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D016159:Tumor Suppressor Protein p53; D008156:Luciferases