EXPRESSION OF CARBONIC-ANHYDRASE-II (CA-II) PROMOTER REPORTER FUSION GENES IN MULTIPLE TISSUES OF TRANSGENIC MICE DOES NOT REPLICATE NORMALPATTERNS OF EXPRESSION INDICATING COMPLEXITY OF CA-II REGULATION IN-VIVO

Although the proximal, 5' 115 bp of the human carbonic anhydrase II (C A II) gene was sufficient for expression of a reporter gene in some tr ansfected cell lines, we found previously that 1100 bp of this promote r (or 500 bp of the mouse CA II promoter) was not sufficient for expre ssion in transgenic mice. We have now studied the expression of linked reporter genes in mice transgenic for either (I) II kb of the human 5 ' promoter or (2) 8 kb of the human 5' promoter with mouse sequences f rom the first exon, part of the first intron (since a CpG island spans this region), and the 3' sequences of the gene. Expression was found in both cases, but the tissue specificity was not appropriate for CA I I. Although there was a difference in the sensitivity of the assays us ed, the first construct led to expression in many tissues, while the s econd construct was expressed only in spleen. These findings indicate considerable complexity of DNA control regions for in vivo CA II expre ssion.