Identification of a novel splicing form of zebrafish p73 having a strong transcriptional activity.
p73 is a transcriptional activator related to tumor suppressor p53 and regulates differentiation, cell-cycle arrest, and apoptosis. Recently, zebrafish p73 (zp73alpha) was isolated and shown to be required for zebrafish embryogenesis. In this study, we isolated a novel splicing-variant of zp73 mRNA, which was generated by the use of an alternative splicing acceptor site, and designated it as zp73theta;. The zp73theta; mRNA encoded a carboxy-terminal structure distinct from that of zp73alpha. Whereas the expression level of zp73theta; mRNA was much lower than that of zp73alpha in zebrafish adult tissues, it was relatively high and fluctuated during embryogenesis. Using Saos-2 cells for a transient reporter assay, we found that zp73theta;, but not zp73alpha, had strong transcriptional activity when the experiments were performed at 34 degrees C. In addition, zp73theta; had the ability to suppress the growth of Saos-2 cells and to cause the developmental defects in zebrafish. These data indicated that zp73theta; could work as a transcriptional activator in zebrafish.
Satoh
Shinya
S
Department of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
Arai
Ken-Ichi
K
Watanabe
Sumiko
S
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010006:Osteoblasts / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D019154:Protein Splicing / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000502:physiology*; D015027:Zebrafish / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D020033:Protein Isoforms; D011994:Recombinant Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C477072:tp73 protein, zebrafish