Cytotype control of Drosophila melanogaster P element transposition: genomic position determines maternal repression.
P element transposition in Drosophila is controlled by the cytotype regulatory state: in P cytotype, transposition is repressed, whereas in M cytotype, transposition can occur. P cytotype is determined by a combination of maternally inherited factors and chromosomal P elements in the zygote. Transformant strains containing single elements that encoded the 66-kD P element protein zygotically repressed transposition, but did not display the maternal repression characteristic of P cytotype. Upon mobilization to new genomic positions, some of these repressor elements showed significant maternal repression of transposition in genetic assays, involving a true maternal effect. Thus, the genomic position of repressor elements can determine the maternal vs. zygotic inheritance of P cytotype. Immunoblotting experiments indicate that this genomic position effect does not operate solely by controlling the expression level of the 66-kD repressor protein during oogenesis. Likewise, P element derivatives containing the hsp26 maternal regulator sequence expressed high levels of the 66-kD protein during oogenesis, but showed no detectable maternal repression. These data suggest that the location of a repressor element in the genome may determine maternal inheritance of P cytotype by a mechanism involving more than the overall level of expression of the 66-kD protein in the ovary.
Misra
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Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Buratowski
R M
RM
Ohkawa
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Rio
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DC
D000818:Animals; D003433:Crosses, Genetic; D004251:DNA Transposable Elements; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D005260:Female; D017344:Genes, Insect; D005809:Genes, Regulator; D006059:Gonadal Dysgenesis / Q000235:genetics; D007247:Infertility, Female / Q000235:genetics; D008297:Male; D008957:Models, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D014170:Transformation, Genetic
D004251:DNA Transposable Elements; D012097:Repressor Proteins