RESUMO
The nucleotide sequence of the Drosophila melanogaster suppressor of sable [su(s)] gene has been determined. Comparison of genomic and cDNA sequences indicates that an approximately 7,860-nucleotide primary transcript is processed into an approximately 5-kb message, expressed during all stages of the life cycle, that contains an open reading frame capable of encoding a 1,322-amino-acid protein of approximately 150 kDa. The putative protein contains an RNA recognition motif-like region and a highly charged arginine-, lysine-, serine-, aspartic or glutamic acid-rich region that is similar to a region contained in several RNA-processing proteins. In vitro translation of in vitro-transcribed RNA from a complete cDNA yields a product whose size agrees with the size predicted by the open reading frame. Antisera against su(s) fusion proteins recognize the in vitro-translated protein and detect a protein of identical size in the nuclear fractions from tissue culture cells and embryos. The protein is also present in smaller amounts in cytoplasmic fractions of embryos. That the su(s) protein has regions similar in structure to RNA-processing protein is consistent with its known role in affecting the transcript levels of those alleles that it suppresses.
Assuntos
Proteínas de Transporte/genética , Drosophila melanogaster/genética , Genes Supressores , RNA/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , DNA/genética , DNA/isolamento & purificação , Drosophila melanogaster/crescimento & desenvolvimento , Éxons , Biblioteca Gênica , Humanos , Íntrons , Dados de Sequência Molecular , RNA/genética , Splicing de RNA , Proteínas de Ligação a RNA , Mapeamento por Restrição , Ribonucleoproteínas/genética , Ribonucleoproteínas Nucleares Pequenas , Homologia de Sequência do Ácido Nucleico , Transcrição GênicaRESUMO
A substantial fraction, perhaps 50% or more, of spontaneous mutations in Drosophila melanogaster have been shown by molecular analyses to be associated with the presence of a transposable element (TE) inserted into the affected gene. We are interested in the molecular structure of induced mutations in Drosophila, in particular whether TEs are also responsible for a significant proportion of chemically-induced mutations. We report here the molecular analysis of 58 mutations at the RpII215 locus induced with EMS or ENU. While we find evidence for moderately sized deletions at this locus (in 3/58, or 5% of the examined mutants), we failed to detect any mutations which were associated with an insertion event. It may be the case that induced mutations are qualitatively different from spontaneous mutations.