title: Evolutionary analysis of the cis-regulatory region of the spicule matrix gene SM50 in strongylocentrotid sea urchins.
abstract: An evolutionary analysis of transcriptional regulation is essential to understanding the molecular basis of phenotypic diversity. The sea urchin is an ideal system in which to explore the functional consequence of variation in cis-regulatory sequences. We are particularly interested in the evolution of genes involved in the patterning and synthesis of its larval skeleton. This study focuses on the cis-regulatory region of SM50, which has already been characterized to a considerable extent in the purple sea urchin, Strongylocentrotus purpuratus. We have isolated the cis-regulatory region from 15 individuals of S. purpuratus as well as seven closely related species in the family Strongylocentrotidae. We have performed a variety of statistical tests and present evidence that the cis-regulatory elements upstream of the SM50 gene have been subject to positive selection along the lineage leading to S. purpuratus. In addition, we have performed electrophoretic mobility shift assays (EMSAs) and demonstrate that nucleotide substitutions within Element C affect the ability of nuclear proteins to bind to this cis-regulatory element among members of the family Strongylocentrotidae. We speculate that such changes in SM50 and other genes could accumulate to produce altered patterns of gene expression with functional consequences during skeleton formation.
authors.affiliation: Department of Biology, Denison University, Granville, OH 43023, USA.
authors.forename: Jenna
authors.initials: J
authors.lastname: Walters
authors.forename: Elaine
authors.initials: E
authors.lastname: Binkley
authors.forename: Ralph
authors.initials: R
authors.lastname: Haygood
authors.forename: Laura A
authors.initials: LA
authors.lastname: Romano
mesh_terms: D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D016326:Extracellular Matrix Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D011485:Protein Binding; D012617:Sea Urchins / Q000145:classification / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D012641:Selection, Genetic; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D047270:Strongylocentrotus purpuratus / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: D017931:DNA Primers; D016326:Extracellular Matrix Proteins; C051691:SM50 protein, sea urchin; D004247:DNA