tailieunhanh - Báo cáo khoa học: cN-crystallin and the evolution of the bc-crystallin superfamily in vertebrates

Thebandccrystallins are evolutionarily related families of proteins that make up a large part of the refractive structure of the vertebrate eye lens. Each family has a distinctive gene structure that reflects a history of succes-sive gene duplications. A survey ofc-crystallins expressed in mammal, rep-tile, bird and fish species (particularly in the zebrafish, Danio rerio) has led to the discovery of cN-crystallin, an evolutionary bridge between theband cfamilies. | iFEBS Journal cN-crystallin and the evolution of the bc-crystallin superfamily in vertebrates Graeme Wistow1 Keith Wyatt1 Larry David2 Chun Gao1 Orval Bateman3 Steven Bernstein4 Stanislav Tomarev1 Lorenzo Segovia5 Christine Slingsby3 and Thomas Vihtelic6 1 NationalEye Institute National institutes of Health Bethesda MD USA 2 Oregon Health Sciences University Portland OR USA 3 Department of Crystallography Birkbeck College London UK 4 Department of Ophthalmology University of Maryland Schoolof Medicine Baltimore MD USA 5 IBT UNAM Col. Chamilpa Cuernavaca Morelos Mexico 6 Department of BiologicalSciences University of Notre Dame Notre Dame IN USA Keywords crystallin eye gene structure intron loss lens Correspondence G. Wistow Section on Molecular Structure and FunctionalGenomics NationalEye Institute Bg 7 Rm 201 National institutes of Health Bethesda MD 20892-0703 USA Tel 1 301 402 3452 Fax 1 301 496 0078 E-mail graeme@ Received 21 January 2005 revised 23 February 2005 accepted 8 March 2005 doi The b and y crystallins are evolutionarily related families of proteins that make up a large part of the refractive structure of the vertebrate eye lens. Each family has a distinctive gene structure that reflects a history of successive gene duplications. A survey of y-crystallins expressed in mammal reptile bird and fish species particularly in the zebrafish Danio rerio has led to the discovery of yN-crystallin an evolutionary bridge between the b and y families. In all species examined yN-crystallins have a hybrid gene structure half b and half y and thus appear to be the missing link between the b and y crystallin lineages. Overall there are four major classes of y-crystallin the terrestrial group including mammalian yA-F the aquatic group the fish yM-crystallins the yS group and the novel yN group. Like the evolutionarily ancient b-crystallins but unlike the terrestrial yA-F and aquatic yM groups both the yS and yN crystallins