SummaryTP5, aPelement inserted in the telomere-associated sequences of the X chromosome, represses the excision of otherPelements in the germ line through a combination of maternal and zygotic effects. The maternal component of this repression is impaired by heterozygous mutations in theaubergineandSuppressor of variegation 205genes; one mutation in thepiwigene also appears to impair repression. In the female germ line, the level ofTP5mRNA is increased by these impairing mutations. The impairingaubergineandpiwimutations also increase the level of germ-line mRNA fromCP, a transgene that encodes theP-element transposase; however, theSuppressor of variegation 205mutation does not. These findings are discussed in terms of a model ofP-element regulation that involves post-transcriptional and chromatin re-organizing events mediated by maternally transmitted small RNAs derived from the telomericPelement.