Characterization of a Splice Variant of Metastasis-Associatedh-mtsl (S100A4)Gene Expressed in Human Infiltrating Carcinomas of the Breast

摘要

Theh-mtsl (S100A4)is a member of the S100 gene family, coding for a calcium-binding protein. It is a metastasis-associated gene whose expression shows strong correlation with the proliferative potential and invasive and metastatic ability of cancers. In a proportion of human intraductal carcinomas of the breast, a shorter varianth-mtsltranscript (h-mtslv) of approximately 450 nucleotides is expressed. We have characterized the transcript using reverse transcriptase-polymerase chain reaction employing exon-specific oligonucleotides. We show here that the noncoding exon 1a/1b is lost in the variant cDNA. Exons 2 and 3, which code for the protein, seem to be present in the variant isoform. The RT-PCR products obtained using exons 2- and 3-specific oligonucleotides showed a high degree of sequence homology with exons 2 and 3 of theh-mtslgene. The expression of the variant transcript could be influencing disease progression, albeit not as effectively as the normal unsplicedh-mtsltranscript.