Gene sharing by delta-crystallin and argininosuccinate lyase.
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Piatigorsky J, O'Brien WE, Norman BL, Kalumuck K, Wistow GJ, Borras T, Nickerson JM, Wawrousek EF
Gene sharing by delta-crystallin and argininosuccinate lyase.
Proc Natl Acad Sci U S A. 1988 May;85(10):3479-83.
- PubMed ID
- 3368457 [ View in PubMed]
- Abstract
The lens structural protein delta-crystallin and the metabolic enzyme argininosuccinate lyase (ASL; L-argininosuccinate arginine-lyase, EC 4.3.2.1) have striking sequence similarity. We have demonstrated that duck delta-crystallin has enormously high ASL activity, while chicken delta-crystallin has lower but significant activity. The lenses of these birds had much greater ASL activity than other tissues, suggesting that ASL is being expressed at unusually high levels as a structural component. In Southern blots of human genomic DNA, chicken delta 1-crystallin cDNA hybridized only to the human ASL gene; moreover, the two chicken delta-crystallin genes accounted for all the sequences in the chicken genome able to cross-hybridize with a human ASL cDNA, with preferential hybridization to the delta 2 gene. Correlations of enzymatic activity and recent data on mRNA levels in the chicken lens suggest that ASL activity depends on expression of the delta 2-crystallin gene. The data indicate that the same gene, at least in ducks, encodes two different functions, an enzyme (ASL) and a structural protein (delta-crystallin), although in chickens specialization and separation of functions may have occurred.