Regulation of the murine αA-crystallin promoter in transgenic mice

Abstract

To identify sequences necessary for lens-specific gene expression, lines of transgenic mice were generated which contain murine αA-crystallin promoter sequences [−111 to +46 (α111), −88 to +46 (α88), and −34 to +46 (α34)] fused to the bacterial chloramphenicol acetyltransferase (CAT) gene and CAT expression was analyzed. Mice carrying the α111-CAT or the α88-CAT fusion transgene expressed CAT exclusively in lens, except for one line containing α111-CAT, which expressed low levels of CAT in several nonlenticular tissues. Transcription from these promoters in lens initiated at the same site as the endogenous αA-crystallin promoter. In one line of mice α88-CAT transgene became active in the lens during embryonic development at approximately the same time that the αA-crystallin gene normally begins to be expressed. In contrast, the α34-CAT fusion transgene, containing the TATA box but no sequences further upstream, was inactive in transgenic mice. Our data suggest that 134 bp of sequence (−88 to +46) in the murine αA-crystallin gene is sufficient to provide lens specificity, although we cannot rule out the possibility that other sequences also contribute to promoter function.