Identification of alternatively spliced Act1 and implications for its roles in oncogenesis.
Act1 (also called CIKS) is a recently identified molecule, which activates NF-kappaB and AP-1. Here, we identified alternatively spliced Act1 that lacked the exon 2 encoding the first nine amino acids in the amino terminus of the protein. Compared to full-length Act1, this truncated Act1 appeared to be equally active. We demonstrated further that only the spliced Act1 was detected in cDNA libraries derived from human fetal brain, liver, leukocytes, and bone marrow. In contrast, both the spliced and full-length Act1 templates were detected in a variety of human cancer cell lines. The expression of both the spliced and full-length transcripts was detected at 4-h time point, following the treatment of endothelial cells with tumor necrosis factor-alpha, interleukin-1beta or bacterial endotoxin. Notably, the dominant amounts of the spliced Act1 over the full-length Act1 were amplified from both the cancer cell mRNAs and the stimulated endothelial cell mRNAs. Taken together with the act1 chromosome localization at the 6q21 subregion, our findings indicate that the newly identified alternatively spliced Act1 is a major transcript of the molecule and that Act1 may play important roles in oncogenesis.
Xia
Yi-Feng
YF
Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai, China.
Li
Yi-Dan
YD
Li
Xiaoxia
X
Geng
Jian-Guo
JG
D048868:Adaptor Proteins, Signal Transducing; D017398:Alternative Splicing; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D002460:Cell Line; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005091:Exons / Q000235:genetics; D015723:Gene Library; D017930:Genes, Reporter; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism; D009369:Neoplasms / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D007375:Interleukin-1; D008070:Lipopolysaccharides; D016328:NF-kappa B; C414202:TRAF3IP2 protein, human; D018808:Transcription Factor AP-1; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D014409:Tumor Necrosis Factor-alpha