crystallin beta B2
The information on this page was automatically extracted from online scientific databases.
From NCBI Gene:
Crystallins are separated into two classes: taxon-specific, or enzyme, and ubiquitous. The latter class constitutes the major proteins of vertebrate eye lens and maintains the transparency and refractive index of the lens. Since lens central fiber cells lose their nuclei during development, these crystallins are made and then retained throughout life, making them extremely stable proteins. Mammalian lens crystallins are divided into alpha, beta, and gamma families; beta and gamma crystallins are also considered as a superfamily. Alpha and beta families are further divided into acidic and basic groups. Seven protein regions exist in crystallins: four homologous motifs, a connecting peptide, and N- and C-terminal extensions. Beta-crystallins, the most heterogeneous, differ by the presence of the C-terminal extension (present in the basic group, none in the acidic group). Beta-crystallins form aggregates of different sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. This gene, a beta basic group member, is part of a gene cluster with beta-A4, beta-B1, and beta-B3. A chain-terminating mutation was found to cause type 2 cerulean cataracts. [provided by RefSeq, Jul 2008]
Crystallins are the dominant structural components of the vertebrate eye lens.
Covered on Genetics Home Reference:
From NCBI Gene:
- Cataract 3, multiple types
Cataract 3, multiple types (CTRCT3): An opacification of the crystalline lens of the eye that frequently results in visual impairment or blindness. Opacities vary in morphology, are often confined to a portion of the lens, and may be static or progressive. CTRCT3 includes congenital cerulean and sutural cataract with punctate and cerulean opacities, among others. Cerulean cataract is characterized by peripheral bluish and white opacifications organized in concentric layers with occasional central lesions arranged radially. The opacities are observed in the superficial layers of the fetal nucleus as well as the adult nucleus of the lens. Involvement is usually bilateral. Visual acuity is only mildly reduced in childhood. In adulthood, the opacifications may progress, making lens extraction necessary. Histologically the lesions are described as fusiform cavities between lens fibers which contain a deeply staining granular material. Although the lesions may take on various colors, a dull blue is the most common appearance and is responsible for the designation cerulean cataract. Sutural cataract with punctate and cerulean opacities is characterized by white opacification around the anterior and posterior Y sutures, and grayish and bluish, spindle shaped, oval punctate and cerulean opacities of various sizes arranged in lamellar form. The spots are more concentrated towards the peripheral layers and do not delineate the embryonal or fetal nucleus. Phenotypic variation with respect to the size and density of the sutural opacities as well as the number and position of punctate and cerulean spots is observed among affected subjects. [MIM:601547]