The transcripts of zeta-crystallin, a lens protein related to the alcohol dehydrogenase family, are altered in a guinea-pig hereditary cataract.
Zeta-Crystallin, a major component of the guinea-pig lens proteins, is distantly related to the enzymes of the zinc-containing alcohol dehydrogenase family (ADH). Analysis of the structural similarities between zeta-crystallin and ADH reveals that while characteristics important in maintaining the tertiary structure of the molecule appear conserved, the amino acids binding the catalytic zinc atom are absent in zeta-crystallin. Significantly, zeta-crystallin does not have ADH activity. Previous studies showed that the zeta-crystallin protein is modified in the lens of guinea-pigs affected with an autosomal dominant hereditary cataract. We have further investigated the molecular origin of the lens defect by examining the steady-state levels of zeta-crystallin transcripts in normal and mutant eyes. Our data indicate that no normal zeta-crystallin mRNA is present in the lens of the homozygous animals; instead, a cross-hybridizing lower molecular weight mRNA is detected at significantly reduced concentrations. Heterozygous lenses exhibit both mRNA species.
Borrás
T
T
Laboratory of Mechanisms of Ocular Diseases, National Eye Institute, National Institutes of Health, Bethesda, MD 20892.
Jörnvall
H
H
Rodokanaki
A
A
Gonzalez
P
P
Rodriguez
I
I
Hernandez-Calzadilla
C
C
D000595:Amino Acid Sequence; D000818:Animals; D002386:Cataract / Q000235:genetics* / Q000378:metabolism; D003459:Crystallins / Q000235:genetics*; D006168:Guinea Pigs; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012313:RNA / Q000032:analysis; D014158:Transcription, Genetic
D003459:Crystallins; D012313:RNA