Drosophila ribosomal RNA genes function as an X-Y pairing site during male meiosis.
In Drosophila melanogaster males, the sex chromosomes pair during meiosis in the centric X heterochromatin and at the base of the short arm of the Y (YS), in the vicinity of the nucleolus organizers. X chromosomes deficient for the pairing region segregate randomly from the Y. In this report we show that a single ribosomal RNA (rRNA) gene stimulates X-Y pairing and disjunction when inserted onto a heterochromatically deficient X chromosome by P element-mediated transformation. We also show that insert-containing X chromosomes pair at the site of insertion, that autosomal rDNA inserts do not affect X-Y pairing or disjunction, and that the strength of an X pairing site is proportional to the dose of ectopic rRNA genes. These results demonstrate that rRNA genes can promote X-Y pairing and disjunction and imply that the nucleolus organizers function as X-Y pairing sites in wild-type Drosophila males.
McKee
B D
BD
Department of Biology, University of Wisconsin, Eau Claire 54701.
Karpen
G H
GH
D000818:Animals; D015139:Blotting, Southern; D003433:Crosses, Genetic; D004251:DNA Transposable Elements; D004275:DNA, Ribosomal / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology; D005260:Female; D005796:Genes; D008297:Male; D008540:Meiosis; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D012335:RNA, Ribosomal / Q000235:genetics*; D014158:Transcription, Genetic; D014960:X Chromosome; D014998:Y Chromosome
D004251:DNA Transposable Elements; D004275:DNA, Ribosomal; D012335:RNA, Ribosomal