Localized expression of carbonic anhydrase genes in liver and muscle detected by hybridization in situ

Abstract

Carbonic anhydrase isoenzymes have previously been localized in different tissues using histochemical techniques which involve the detection of enzyme activity or reacting with specific antiserum (using immunoperoxidase and immunofluorescence techniques). A combination of these methods applied to rat muscle has shown that carbonic anhydrase 111 (CAIII) occurs predominantly in the type I (slow fibres). In rat liver, digitonin perfusion has provided evidence that CAIII predominates in the perivenous region, but is also present at lower concentrations in other areas. These same experiments together with studies using immunofluorescencc showed carbonic anhydrase I1 (CAII) to be localized only in the perivenous region. An effective protocol for hybridization iri sitir using S labelled probe and paraformaldehyde fixation is given in Moorman et al. (1988). Hybridization iri sitir of biotinlabelled rat CAM cDNA was carried out using a slight modification of the method of Zimmerman rt al. (1988). After autoradiography for '?S, and streptavidin/alkalinc phosphatase colour development for biotin, CAlll mRNA can be demonstrated in liver and muscle as shown in Fig. 1 .