title: Evolution of regulatory elements producing a conserved gene expression pattern in Caenorhabditis.
abstract: Natural selection acts at the level of function, not at the logistical level of how organisms achieve a particular function. Consequently, significant DNA sequence and regulatory differences can achieve the same function, such as a particular gene expression pattern. To investigate how regulatory features underlying a conserved function can evolve, we compared the regulation of a conserved gene expression pattern in the related species Caenorhabditis elegans and C. briggsae. We find that both C. elegans and C. briggsae express the ovo-related zinc finger gene lin-48 in the same pattern in hindgut cells. However, the regulation of this gene by the Pax-2/5/8 protein EGL-38 differs in two important ways. First, specific differences in the regulatory sequences of lin-48 result in the presence of two redundant EGL-38 response elements in C. elegans, whereas the redundancy is absent in C. briggsae. Second, there is a single egl-38 gene in C. briggsae. In contrast, the gene is duplicated in C. elegans, with only one copy retaining the ability to regulate lin-48 in vivo. These results illustrate molecular changes that can occur despite maintenance of conserved gene function in different species.
authors.affiliation: Department of Molecular Genetics, Ohio State University, Columbus, OH 43210, USA.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Wang
authors.forename: Jennifer F
authors.initials: JF
authors.lastname: Greenberg
authors.forename: Helen M
authors.initials: HM
authors.lastname: Chamberlin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002107:Caenorhabditis / Q000235:genetics* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D020440:Gene Duplication; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012641:Selection, Genetic; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D019076:Transgenes
chemical_list: D029742:Caenorhabditis elegans Proteins; D018076:DNA, Complementary; C434744:Lin-48 protein, C elegans; D014157:Transcription Factors; C497470:egl-38 protein, C elegans