Identification of a lens-specific regulatory region (LSR) of the murine alpha B-crystallin gene.
Previous studies have shown that the -661/+44 sequence of the murine alpha B-crystallin gene contains a muscle-preferred enhancer (-426/-257) and can drive the bacterial chloramphenicol acetyltransferase (CAT) gene in the lens, skeletal muscle and heart of transgenic mice. Here we show that transgenic mice carrying a truncated -164/+44 fragment of the alpha B-crystallin gene fused to the CAT gene expressed exclusively in the lens; by contrast mice carrying a -426/+44 fragment of the alpha B gene fused to CAT expressed highly in the lens, skeletal muscle and heart, and slightly in the lung, brain, kidney, spleen and liver. DNase I protection experiments indicated that the -147/-118 sequence is protected by nuclear proteins from alpha TN4-1 lens cell line, but not by nuclear proteins from myotubes of the C2C12 cell line. Site directed mutagenesis of this sequence decreased promoter activity in transiently-transfected lens cells, consistent with this sequence being a lens-specific regulatory region (LSR). We conclude that the -426/-257 enhancer is required for expression in skeletal muscle, heart and possibly other tissues, and that the -164/+44 sequence of the alpha B-crystallin gene is sufficient for expression in the lens of transgenic mice.
Gopal-Srivastava
R
R
Laboratory of Molecular and Developmental Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892.
Piatigorsky
J
J
D000818:Animals; D001483:Base Sequence; D003459:Crystallins / Q000235:genetics*; D004247:DNA; D003850:Deoxyribonuclease I; D007908:Lens, Crystalline / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid
D003459:Crystallins; D004247:DNA; D003850:Deoxyribonuclease I