Kim RY, Lietman T, Piatigorsky J, Wistow GJ. Structure and expression of the duck alpha-enolase/tau-crystallin-encoding gene.
Gene 1991;
103:193-200. [PMID:
1889745 DOI:
10.1016/0378-1119(91)90273-e]
[Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In the duck, the glycolytic enzyme, alpha-enolase (alpha ENO) and the lens structural protein, tau-crystallin (tau CRY), are products of the same gene, an example of protein multi-functionality. We report that duck alpha ENO/tau CRY mRNA levels are developmentally regulated: alpha ENO/tau CRY mRNA levels in the lens increase over those in the liver by embryonic day 14 and, within the lens, are higher in the lens epithelium than in fiber cells. We determined the structure of the duck alpha ENO/tau CRY-encoding gene (alpha ENO/tau CRY), sequenced 1 kb of 5'-flanking region, and demonstrated that this region contains a functional promoter. The gene is 13 kb in size and is composed of twelve exons; the exon organization is identical to that of mammalian enolase-encoding genes. A fragment of 5'-flanking region (-803/+3) containing three CCAAT boxes and a TATA box was able to activate transcription of a heterologous reporter gene when transfected into cultured lens cells. However, in spite of greater quantities of alpha ENO/tau CRY mRNA and protein in the lens, the promoter was equally active in primary cultures of embryonic lens, liver and fibroblast cells. Since the cultured cells unexpectedly lost the restricted pattern of alpha ENO/tau CRY mRNA levels observed in vivo, evaluation of the promoter's tissue specificity was precluded.
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