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human Smad family genes である hSmad5 gene のcDNA、ゲノム構造、プロモーター領域とヒト腫瘍での変異解析: 弦間昭彦^1,2 、萩原弘一¹、 William P. Bennett¹, and Curtis C. Harris¹ (¹Laboratory of Human Carcinogenesis, NCI, NIH, ²日本医科大学第四内科)

cDNA sequence, genomic structure, and promoter region of hSmad5 gene, a member of human Smad family genes, and mutation analysis in human tumors: Akihiko Gemma^1,2, Koichi Hagiwara¹, William P. Bennett¹, and Curtis C. Harris¹ (¹Laboratory of Human Carcinogenesis, NCI, NIH. ²Fourth department of internal medicine, Nippon Medical Center.)

Mad-related proteins were important molecules implicated in transforming growth factor β(TGF-β superfamily signal pathways. We obtained full length of cDNA of hSmad5, a member of human Mad-related gene in human, by the reported expressed sequence tag (EST) clone, EST database search and a rapid amplification of cDNA ends (RACE) and then determined the genomic structure of the gene and designed the intron based primer pairs for each exons of the eitire coding region of the gene in order to facilitate the mutation analysis of the gene in human tumors. 5'RACE showed two different transcrts. This gene has 8 exons and the coding region is from exon 3 to exon 8. Two different transcription was due to alternative splicing. We have cloned and characterized the hSmad5 promoter region by screening a human genomic library and luciferase assay. The first 200 bp of 5' flanking sequence is very GC rich. Upstream of the sequence become AT rich. No homozygous deletions nor point mutations were found in 51 human tumor cell lines including 20 TGF-βresistant lines in PCR-SSCP. These results suggested that the hSmad5 gene is not commonly mutated and that the loss of TGF-βresponsiveness is not due to hSmad5 gene alteration.