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Open Access Gene family update

The human crystallin gene families

Graeme Wistow

Author Affiliations

Section on Molecular Structure and Functional Genomics, National Eye Institute, Bg 6, Rm 106, National Institutes of Health, Bethesda, MD, 20892-0608, USA

Human Genomics 2012, 6:26  doi:10.1186/1479-7364-6-26

Published: 1 December 2012

Abstract

Crystallins are the abundant, long-lived proteins of the eye lens. The major human crystallins belong to two different superfamilies: the small heat-shock proteins (α-crystallins) and the βγ-crystallins. During evolution, other proteins have sometimes been recruited as crystallins to modify the properties of the lens. In the developing human lens, the enzyme betaine-homocysteine methyltransferase serves such a role. Evolutionary modification has also resulted in loss of expression of some human crystallin genes or of specific splice forms. Crystallin organization is essential for lens transparency and mutations; even minor changes to surface residues can cause cataract and loss of vision.

Keywords:
Crystallins; Lens; Cataract; Evolution; Pseudogene; Heat-shock; Enzymes