|  | Public Health Safety | Medical Research

The Composition of Beta A3/A1 in a Lens

Beta-crystallin A3 is a protein in humans that is encoded by the CRYBA1 gene. Crystallins are separated into two classes: enzyme and ubiquitous. The ubiquitous class is the group of important proteins in vertebrate eye lenses that sustain the transparency and refractive index of the lenses. Beta A3 crystallin and beta A1 crystallin are both formed from a single mRNA. mRNA is a single strand of messenger ribonucleic acid.

  1. Similarities

    • Beta A3 crystallin and beta A1 crystallin are essentially identical. The A1 crystallin is 17 aa shorter than that of the beta a3 crystallin. The aa represents two strand lengths of mRNA, the building blocks of human DNA. Deletion of certain DNA strands can indicate various eye disease states, according to the Gene Symbol Report for the CRYBA1 gene.

    Crystallin Groupings

    • The lens crystallins of humans and other mammals are divided into alpha, beta and gamma families. The alpha and beta families of lens crystallins are further divided into acidic and basic groups. Seven protein regions exist in crystallins: four homologous recurring salient thematic elements, a connecting peptide, an N-terminal extension and a C-terminal extension.

    Beta crystallins

    • Beta-crystallins are the dominant building blocks of the eye lens of humans and all other vertebrates. They differ by the presence of a C-terminal extension that allows beta crystallins to form aggregates or combinations of different sizes. Beta-crystallins are also capable of self-associating to form dimers, or to form heterodimers with other beta-crystallins.

    Genetic Disease Indicators

    • A Chinese family with progressive childhood cataracts was examined for CRYBA3/A1 mutations. Family history and clinical data were noted. Direct gene sequencing together with multi-point linkage analysis using microsatellite markers flanking the gene was applied to identify the disease-causing mutation. The study by the Eye Center of the 2nd Affiliated Hospital, Medical College of Zhejiang University, Hangzhou, China stated that "this is the first report of a phenotype of progressive nuclear and cortical cataracts related to the CRYBA3/A1 mutation IVS3+1 G>A."

Medical Research - Related Articles