title: The P cytotype in Drosophila melanogaster: a maternally transmitted regulatory state of the germ line associated with telomeric P elements.
abstract: The incomplete P elements TP5 and TP6 are inserted in the TAS repeats near the left telomere of the Drosophila melanogaster X chromosome. These telomeric P elements repress P-induced gonadal dysgenesis and germ-line hypermutability in both sexes. However, their capacity to repress hypermutability is lost when they are transmitted patroclinously in a cross. TP5 and TP6 do not repress P-element activity in somatic cells, nor do they alter the somatic or germ-line phenotypes of P-insertion alleles. In the germ line, these elements suppress the phenotype of a P-insertion allele of the singed gene that is evoked by other P elements, presumably because these other elements encode repressor polypeptides. This suppression is more effective when the telomeric P elements are inherited maternally. Regulation by telomeric P elements parallels that of the P cytotype, a state that represses P-element activity in some strains of Drosophila. This state exists only in the germ line and is maternally transmitted along with the P elements themselves. Regulation by known repressor P polypeptides is not restricted to the germ line and does not require maternal transmission of the relevant P elements. Regulation by telomeric P elements appears to be epistatic to regulation by repressor P polypeptides.
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Saint Paul, Minnesota 55108-1095, USA. simmo004@umn.edu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Simmons
authors.forename: John D
authors.initials: JD
authors.lastname: Raymond
authors.forename: Jarad B
authors.initials: JB
authors.lastname: Niemi
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Stuart
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Merriman
mesh_terms: D000483:Alleles; D000818:Animals; D003433:Crosses, Genetic; D004251:DNA Transposable Elements / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D005854:Germ Cells; D006059:Gonadal Dysgenesis / Q000235:genetics; D008297:Male; D010641:Phenotype; D016615:Telomere / Q000235:genetics*; D019895:Transposases / Q000235:genetics; D014960:X Chromosome / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D019895:Transposases