Structure and lens expression of the gene encoding chicken beta A3/A1-crystallin.
The beta A1- and beta A3-crystallins are major polypeptides in the lenses of vertebrates. We present evidence that a single beta A3/A1 gene encodes these two proteins in the chicken. The beta A3/A1 gene has been sequenced and its functional promoter identified in transfection experiments. The chicken beta A3/A1 gene has the same structure as the human orthologue: six exons with standard splice sites and two alternative start codons from which the protein products are apparently translated. Northern analysis revealed an abundant 0.9-kb transcript in the lenses of 1-2-day-old chickens and no detectable transcripts in the rest of the eye, brain, heart, kidney, liver or skeletal muscle. The 5'-flanking sequence of the chicken beta A3/A1 gene is very similar to that of the human and mouse genes, suggesting conservation of important putative regulatory sequences in addition to the TATA box. A thymidine-rich element (bp -218 to -163) and a potential AP-1-binding site (bp -264 to -258) are present within the chicken 5'-flanking region. A DNA fragment from -382 to +22 of the chicken beta A3/A1 gene is sufficient to promote expression of the bacterial cat gene in transfected chicken primary lens epithelial cells, but not in transfected dermal fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)
Laboratory of Molecular and Developmental Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892.
J B
JB
McDermott
C A
CA
Peterson
J
J
Piatigorsky
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002642:Chick Embryo; D003459:Crystallins / Q000737:chemistry / Q000235:genetics*; D005786:Gene Expression Regulation / Q000235:genetics; D007908:Lens, Crystalline / Q000378:metabolism*; D008969:Molecular Sequence Data; D012150:Polymorphism, Restriction Fragment Length; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics; D038205:beta-Crystallin A Chain
C489108:CRYBA1 protein, human; D003459:Crystallins; D011993:Recombinant Fusion Proteins; D038205:beta-Crystallin A Chain