SEQUENCE COMPARISONS AND FUNCTIONAL-STUDIES OF THE PROXIMAL PROMOTER OF THE CARBONIC-ANHYDRASE-3 (CA3) GENE

Carbonic anhydrase 3 (CA3) is a member of a gene family encoding prote ins which catalyse the hydration of CO, to generate protons and bicarb onate ions for cellular ion transport and pH homeostasis. In mouse emb ryos CA3 is expressed at high levels in notochord and skeletal muscle and here we demonstrate that this pattern of expression is the same in the developing human embryo. To investigate mechanisms controlling CA 3 transcription, we have isolated and compared 2.8 kb of sequence flan king exon 1 from the mouse and human genes. Several segments of high s equence identity >80% have been identified, the longest segments of wh ich represent a proximal promoter region and a putative enhancer eleme nt. We have shown previously that in cultured cells the human 2.8 kb p romoter region imposes high level myogenic specific transcription of a reporter gene. However, we now show that while this promoter region d irected muscle-specific expression in transgenic mouse embryos this wa s subject to position effects. (C) 1998 Elsevier Science B.V. All righ ts reserved.