Structure and evolution of neurexin genes: insight into the mechanism of alternative splicing.
Neurexins are neuron-specific vertebrate proteins with hundreds of differentially spliced isoforms that may function in synapse organization. We now show that Drosophila melanogaster and Caenorhabditis elegans express a single gene encoding only an alpha-neurexin, whereas humans and mice express three genes, each of which encodes alpha- and beta-neurexins transcribed from separate promoters. The neurexin genes are very large (up to 1.62 Mb), with the neurexin-3 gene occupying almost 2% of human chromosome 14. Although invertebrate and vertebrate neurexins exhibit a high degree of evolutionary conservation, only vertebrate neurexins are subject to extensive alternative splicing that uses mechanisms ranging from strings of mini-exons to multiple alternative splice donor and acceptor sites. Consistent with their proposed role in synapse specification, neurexins thus have evolved from relatively simple genes in invertebrates to diversified genes in vertebrates with multiple promoters and extensive alternative splicing.
Tabuchi
Katsuhiko
K
Center for Basic Neuroscience, Department of Molecular Genetics, and Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA.
Südhof
Thomas C
TC
D017398:Alternative Splicing; D000818:Animals; D019143:Evolution, Molecular; D006801:Humans; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA
D009419:Nerve Tissue Proteins