Retrotransposon insertion induces an isozyme of sn-glycerol-3-phosphate dehydrogenase in Drosophila melanogaster (original) (raw)
Related papers
Biochemical Genetics, 1999
Trans effects at the sn-glycerol-3-phosphatedehydrogenase locus (Gpdh) of Drosophilamelanogaster give rise to an increase in GPDHactivity and mRNA from the wild-type allele inheterozygotes with some low-activity alleles. Either the low-activityalleles that induce the effect have a defectiveP-element inserted between the promoter and a downstreamintronic enhancer element or the promoter region is deleted. The trans effect is pairing dependent,characteristic of transvection at some other loci. Thedefective P-elements that mediate transvection arelocated between the promoter and at least up to 6 bp downstream of the transcription startsite. Transvection at Gpdh appears similar to the“enhancer action in trans” mode at theyellow locus.
Nucleic Acids Research, 1989
We present the complete nucleotide and deduced amino acid sequence for the gene encoding Drosophila sn-glycerol-3-phosphate dehydrogenase. A transcription unit of 5kb was identified which is composed of eight protein encoding exons. Three classes of transcripts were shown to differ only in the 3'-end and to code for three protein isoforms each with a different C-terminal amino acid sequence. Each transcript is shown to arise through the differential expression of three isotype-specific exons at the 3'-end of the gene by a developmentally regulated process of 3'-end formation and alternate splicing pathways of the pre-mRNA. In contrast, the 5'-end of the gene is simple in structure and each mRNA is transcribed from the same promoter sequence. A comparison of the organization of the Drosophila and murine genes and the primary amino acid sequence between a total of four species indicates that the GPDH gene-enzyme system is highly conserved and is evolving slowly.
Genes & Development, 1990
Three alleles of the Drosophila melanogaster vermilion (v) gene are suppressed by recessive mutations at the suppressor of sable [su(s)], gene. Previous work has established that these alleles have identical insertions of the 412 retrotransposon in the 5'-untranslated region of the gene. Despite the transposon insertion in an exon, v mutants accumulate trace amounts of apparently wild-type-sized transcripts in a su(s)+ background, and the level of v transcript accumulation is increased by su(s) mutations. Here, we have characterized transcripts from a suppressible v mutant in both su(s)+ and su(s)- backgrounds by S1 nuclease protection experiments and sequence analysis of polymerase chain reaction (PCR) generated cDNA clones. We find that transposon sequences are imprecisely eliminated from v mutant transcripts by splicing at donor and acceptor sites located near the ends of the 412 retrotransposon. Four different 5' donor sites are alternatively spliced to a single 3' a...
Genetical Research, 1996
SummaryThe alcohol dehydrogenase (Adh) gene of Drosophila melanogaster is well suited to be a gene expression reporter system. Adh produces a measurable phenotype at both the enzyme and mRNA levels. We recovered a spontaneous transposable element (TE) insertion mutation near the Adh gene. The insertion is a truncated retroposable element, jockey, inserted upstream of the adult Adh enhancer region. Comparisons between the Adhjockey allele and its direct wild-type ancestral allele were made in an isogenic background (i.e. identical cis and trans factors). Differences in Adhjockey expression compared with the wild-type can be attributed solely to the presence of the jockey element. This jockey insertion results in a decrease in adult mRNA transcript levels in the Adhjockey homozygous lines relative to the wild-type counterpart and accounts for a correlated decrease in alcohol dehydrogenase (ADH) enzyme activity. The larval ADH activity levels are not detectably different.
Molecular Biology and Evolution, 2004
The structural variants of the regulatory and coding regions of the LTR-retrotransposon 1731 are described. Two classes of genomic copies of retrotransposon 1731, with and without frameshifting strategy to express Gag and Pol proteins, were earlier revealed in the D. melanogaster genome. Copies without frameshifting are shown to be evolved from an ancient variant with frameshifting and are widespread in the genomes of the melanogaster complex species. Position of a rare codon responsible for ribosome pausing and efficient frameshifting is identified. Two structural variants of 1731 LTRs were detected in the melanogaster complex species: the predominant structural variant A1A2 of 1731 LTR in the D. melanogaster, D. simulans, and D. sechellia genomes contains duplicated and diverged copies of 28 bp in the U3 region, whereas A1 variant lacking this duplication is expanded in the D. mauritiana genome. Selective expansion of the A1A2 variant was detected in the independently established D. melanogaster cell cultures. A1A2 variant is expressed in embryos, cell culture, and testes, whereas A1 is expressed only in testes of D. melanogaster. Relief of expression of the A1A2 but not A1 variant in the ovaries as a result of mutation in the RNA interference (RNAi) spn-E gene is shown. Thus, expansion of the recently evolved genomic variants of the LTR retrotransposon 1731 possessing a new translation strategy, duplication in the U3 region, and extended profile of expression is revealed.
Primary structure and functional organization of Drosophila 1731 retrotransposon
Nucleic Acids Research, 1988
We have determined the nucleotide sequence of the Drosophila retrotransposon 1 731. 1731 is 4648 bp long and is flanked by 336 bp terminal repeats (LTRs) previously described as being reminiscent of provirus LTRs. The 1731 genome consists of two long open reading frames (ORFs 1 and 2) which slightly overlap each other. The ORF 1 and 2 present similarities with retroviral gag and pol genes respectively as shown by computer analysis. The pol gene exhibits several enzymatic activities in the following order: protease, endonuclease and reverse transcriptase. It is possible that 1731 also encompasses a ribonuclease H activity located between the endonuclease and reverse transcriptase domains. Moreover, comparison of the 1731 pol gene with the pol region of copia shows similarities extending over the protease, endnuclease and reverse transcriptase domains. We show that codon usep in the two retrotransposons is different. Finally, no ORF able to encode an env gene is detected in 1 731.
1731, a new retrotransposon with hormone modulated expression
Nucleic acids research, 1986
We report here the characterisation of 1731, a new copia-like element of Drosophila melanogaster. 1731 was first isolated in a screening for ecdysterone modulated genes. This element is about 4.6 Kb long and is flanked by two long terminal repeats (LTRs) 336 base pairs in length. The whole 1731 element is transcribed into polyA+ RNAs, and these transcripts decrease rapidly upon hormonal treatment. 1731 is moderately repeated in the fly genome and slightly amplified in Kc/cells where extrachromosomal circular forms are found. The LTRs were sequenced in one cloned copy of 1731 and show a structural organisation similar to that of several other copia-like elements and retroviral proviruses. Small nucleotide stretches, similar to those found in Mouse Mammary Tumor Virus LTRs and known to be important in its regulation by a steroid hormone, occur in 1731 LTRs.
The EMBO Journal
Academy of Sciences of the USSR, 117984 Moscow, USSR Communicated by G.P.Georgiev The mobile element jockey is similar in structural organization and coding potential to the LINEs of various organisms. It is transcribed at different stages of Drosophila ontogenesis. The Drosophila LINE family includes active transposable elements. Current models for the mechanism of transposition involve reverse transcription of an RNA intermediate and utilization of elementencoded proteins. As demonstrated here, a 2.23 kb DNA fragment from the region ofjockey encoding the putative reverse transcriptase was stably introduced into an expression system under inducible control of the Escherichia coli lac regulatory elements. We describe the expression of the 92 kDa protein and identify this polypeptide alone as the authentic jockey reverse transcriptase based on some of its physical and enzymic properties. The jockey polymerase demonstrates RNA and DNA-directed DNA polymerase activities but lacks detectable RNase H, has a temperature optimum at 260C, requires Mg2+ or Mn2+ as a cofactor and is inactivated by sulphydryl reagent. The enzyme prefers poly(rC) and poly(rA) as template and 'activated' DNA is not effective.
Doklady. Biochemistry and biophysics, 2004
Retrotransposons of the group Ty3/gypsy constitute a considerable part of eukaryotic transposable elements. Those of them that contain three open reading frames (ORFs) and are similar to the retroviral genes gag , pol , and env of vertebrates are of the greatest interest. A number of structural and functional characteristics of members of this family allow them to be classified in a special group of retroelements-endogenous retroviruses. It has been demonstrated that the retrotransposon MDG4 ( gypsy ) of Drosophila , the best studiedbest-studied representative of endogenous retroviruses, forms infective particles . The product of the third ORF of MDG4 is believed to play a key role in imparting the capability of horizontal transposition to this transposable element [2]; however, its function remains obscure. In view of this, the poorly studied retrotransposon gtwin , which is evolutionarily most closest to MDG4, is of special interest. We cloned gtwin from the D. melanogaster strain G32, whose genome contains an abnormally great number of copies of this element. We found that all copies of this retrotransposon that were cloned from the strain G32 contained a functional third ORF, whereas the gtwin sequences accessible in the Drosophila genome databanks (accession nos. AC006215 and AC107326) carried a nonsense mutation resulting in the appearance of the stop codon in the middle part of its ORF 3. It was assumed that the amplification of the gtwin gene in strain G32 may be related to the presence in its genome of the retrotransposon copies containing a functional third ORF.