EXPRESSION AND CYTOGENETIC LOCALIZATION OF THE HUMAN SM22 GENE (TAGLN)

SM22 is a 22-kDa protein identified variously as SM22, transgelin, WS3 -10, or mouse p27. Though its precise function is unknown, it is abund ant in smooth muscle and so may contribute to the physiology of this w idespread tissue. We found that cosmid 16b6 contains the entire 5.4-kb , five exon human SM22 gene (HGMW-approved symbol, TAGLN), and we cyto genetically localized the gene to chromosome 11q23.2. Northern analysi s of human adult tissues showed that SM22 mRNA is most prevalent in sm ooth muscle-containing tissues, but is also found at lower levels in h eart. The human SM22 promoter contains nuclear factor-binding motifs k nown to regulate transcription in smooth muscle, and human SM22 promot er-luciferase reporter constructs exhibited high transcriptional activ ity in A7r5 or primary canine aortic smooth muscle cells, but show lit tle activity in nonmuscle COS7 cells. In addition, human SM22 promoter activity increased by two-to threefold upon serum stimulation of nonm uscle cells. (C) 1998 Academic Press.