P-element repressor autoregulation involves germ-line transcriptional repression and reduction of third intron splicing.
P cytotype is a regulatory state, characteristic of Drosophila P-strain females, in which P-element transposition is repressed. P cytotype is established maternally in the germ line but is also dependent on the presence of P elements in the zygote. One aspect of P cytotype involves transcriptional repression of the P-element promoter. Here, we show that transcriptional repression by P cytotype in the female germ line occurs by a general promoter-independent mechanism with heterologous promoters carried in P-element vectors. P-cytotype transcriptional repression results in low levels of pre-mRNA and a reduction in splicing of the P-element third intron (IVS3)-containing mRNA, thus causing an increase in the proportion of 66-kD repressor mRNA. Increased retention of IVS3 in P cytotype would result in an autoregulatory loop of 66-kD repressor production. This combination of germ-line transcriptional repression and splicing control provides a mechanism to maintain repression during the maternal inheritance of P cytotype. These findings suggest that transcriptional repression may play an additional role in the regulation of gene expression, namely allowing alteration of pre-mRNA splicing patterns.
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Department of Molecular and Cell Biology, University of California, Berkeley 94720-3204, USA.
Schiff
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Rio
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D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D017403:In Situ Hybridization; D007438:Introns; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics; D012097:Repressor Proteins / Q000502:physiology*; D018626:Retroelements; D014158:Transcription, Genetic
D017931:DNA Primers; D012333:RNA, Messenger; D012097:Repressor Proteins; D018626:Retroelements