A class III myosin expressed in the retina is a potential candidate for Bardet-Biedl syndrome.
Class III myosins are actin-based motors with amino-terminal kinase domains. Expression of these motors is highly enhanced in retinal photoreceptors. As mutations in the gene encoding NINAC, a Drosophila melanogaster class III myosin, cause retinal degeneration, human homologs of this gene are potential candidates for human retinal disease. We have recently reported the cloning of MYO3A, a human myosin III expressed predominantly in the retina and retinal pigmented epithelium [1]. The map locus of MYO3A is close to, but does not overlap, that of human Usher's 1F [2]. Here we introduce a shorter class III myosin isoform, MYO3B, which is expressed in the retina, kidney, and testis. We describe the cDNA sequence, genomic organization, and splice variants of MYO3B expressed in the human retina. A product of 36 exons, MYO3B has several splice variants containing either one or two calmodulin binding (IQ) motifs in the neck domain and one of three predominant tail variations: a short tail ending just past the second IQ motif, or two alternatively spliced longer tails. MYO3B maps to 2q31.1-q31.2, a region that overlaps the locus for a Bardet-Biedl syndrome (BBS5) linked to markers at 2q31 [3].
Dosé
Andréa C
AC
Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720-3200, USA. acdose@socrates.berkeley.edu
Burnside
Beth
B
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D020788:Bardet-Biedl Syndrome / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D005091:Exons; D005260:Female; D015870:Gene Expression; D005796:Genes / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D007438:Introns; D008297:Male; D008969:Molecular Sequence Data; D018995:Myosin Heavy Chains / Q000235:genetics*; D025102:Myosin Type III; D020033:Protein Isoforms / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
C491723:MYO3B protein, human; D020033:Protein Isoforms; D012333:RNA, Messenger; D025102:Myosin Type III; D018995:Myosin Heavy Chains