Genotypic effects, maternal effects and grand-maternal effects of immobilized derivatives of the transposable element mariner

• Published in: Genetics (Austin) Vol. 140; no. 1; pp. 183 - 192
• Main Authors: Lohe, A.R, Lidholm, D.A, Hartl, D.L
• Format: Journal Article
• Language: English
• Published: United States Genetics Society of America 01.05.1995
• Subjects: Animals; DNA Transposable Elements - genetics; Drosophila melanogaster; Drosophila melanogaster - genetics; Eye Color - genetics; Female; Genes; Genes, Insect; genetic change; genetic effects; genetic integration; genetic transformation; Genetics; Genotype; germ cells; germline excision; germline transformation; Insects; insertion; Investigations; Male; maternal effect; Mutagenesis, Insertional; promoter regions; recombinant DNA; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Repetitive Sequences, Nucleic Acid; Sequence Deletion; Transformation, Genetic; transposition; transposons
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/140.1.183

The baseline rate of spontaneous integration of the autonomous manner element Mos1 into the germline of Drosophila melanogaster estimated as 16 +/- 596 (mean +/- SE) among fertile G0 flies. However, the transformation rate is reduced approximately 20-fold in Mos1 constructs with exogenous DNA in the size range 5-12 kb inserted into the Sad site. To provide alternative Mos1 helper plasmids for transformation experiments, two types of Mos1-promoter fusions were constructed: hsp-70:Mos1 and hsp26-Sgs3:Mos1. The former has the Mos1 coding region driven by the hsp70 heat-shock promoter; the latter has it driven by the basal Sgs3 promoter under the control of the hsp26 female-germline specific transcriptional regulator. When introduced into D. melanogaster by P-element-mediated germline transformation, these elements are unable to transpose or excise in the presence of autonomous Mos1-related elements (they are "marooned") because the 5' inverted repeat of Mos1 is missing. As expected, the hsp26-Sgs3:Mos1 fusions exhibit a significantly greater rate of germline excision of a target mariner element than do the hsp70:Mos1 fusions. Unexpectedly, the rate of excision of target manner elements induced by hsp26-Sgs3:Mos1 is the same in the male germline as in the female germline. Both hsp:Mos1 fusions show strong germline expression and a maternal effect of the manna transposase. A significant grand-maternal effect of the hsp:Mos1 fusions was also detected as a result of a maternal effect on the germline of the F1 progeny. Among flies carrying the promoter fusions inherited maternally, about three-quarters of the overall rate of germline excision derives from the direct genotypic effect and about one-quarter results from the grand-maternal effect. Despite the strong somatic expression of the hsp:Mos1 fusions, manna transformants carrying a white+ the gene at the SacI site remained stable in the soma.