The Sex-lethal gene homologue in Chrysomya rufifacies is highly conserved in sequence and exon-intron organization.
A great variety of sex determination mechanisms exists in insect species. In Drosophila melanogaster sex is determined by the ratio between X chromosomes and autosomes, while in the blowfly Chrysomya rufifacies it is maternally determined. A cascade of genes which are involved in sex determination has been identified in D. melanogaster with the Sex-lethal gene (Sxl) as the key gene. We screened genomic libraries of C. rufifacies with a probe of the Sxl gene from D. melanogaster and isolated a genomic region that included most of the homologous gene. DNA- and protein-sequence comparison showed a high percent identity between the Chrysomya and the Drosophila gene. Up to 90% identity of the amino acid sequences was found in the region that contained the RNA-binding domains. The degree of identity is much lower outside of this functionally important region (18% identity). cDNA analysis showed a highly conserved exon-intron structure between the two species, although sex-specific splicing as used in D. melanogaster for the regulation of Sxl activity, could not be detected in C. rufifacies.
Müller-Holtkamp
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Zoologisches Institut, Universität Kiel, Germany.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003433:Crosses, Genetic; D017931:DNA Primers; D004175:Diptera / Q000235:genetics* / Q000502:physiology; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology; D005091:Exons; D005260:Female; D005786:Gene Expression Regulation; D017344:Genes, Insect; D005804:Genes, Lethal; D007301:Insect Hormones / Q000235:genetics*; D007438:Introns; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012326:RNA Splicing; D016601:RNA-Binding Proteins; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012732:Sex Determination Analysis; D014960:X Chromosome
D017931:DNA Primers; D029721:Drosophila Proteins; D007301:Insect Hormones; D016601:RNA-Binding Proteins; C067777:Sxl protein, Drosophila