CLONING OF THE ALPHA-A-CRYSTALLIN GENES OF A BLIND CAVE FORM AND THE EPIGEAN FORM OF ASTYANAX-FASCIATUS - A COMPARATIVE-ANALYSIS OF STRUCTURE, EXPRESSION AND EVOLUTIONARY CONSERVATION
M. Behrens et al., CLONING OF THE ALPHA-A-CRYSTALLIN GENES OF A BLIND CAVE FORM AND THE EPIGEAN FORM OF ASTYANAX-FASCIATUS - A COMPARATIVE-ANALYSIS OF STRUCTURE, EXPRESSION AND EVOLUTIONARY CONSERVATION, Gene, 216(2), 1998, pp. 319-326
In the present study we have analyzed the integrity and expression of
the alpha A-crystallin gene, that codes for a major structural compone
nt of the lens, in a blind cave form of the teleostean fish, Astyanax
fasciatus. This is the first alpha A-crystallin gene cloned from a tel
eostean fish. Sequence comparison of this cave-form gene with its epig
ean conspecific and with homologs of distantly related taxa has illust
rated conservation of regulatory and coding regions. Although no cryst
allin proteins are produced in the lens of the cave form, and the mRNA
of this gene could not be detected by in situ hybridization of differ
ent developmental stages, the promoter region of cave-fish alpha A-cry
stallin is functionally intact. The deduced amino-acid sequence of the
alpha A-crystallin gene of the cave form differs from that of its epi
gean conspecific at only one position (139). This is within an importa
nt, small heat-shock protein-related region, HCR2. A comparison of the
5'-flanking regions of the A. fasciatus alpha A-crystallin gene with
the chicken homolog revealed the high conservation of lens-specific re
gulatory sequences and further demonstrates the evolutionary conservat
ion of this gene. (C) 1998 Elsevier Science B.V. All rights reserved.