NATURALLY-OCCURRING TESTIS-SPECIFIC HISTONE H3 ANTISENSE TRANSCRIPTS IN DROSOPHILA

While analysing the transcription of the cluster of cell-cycle regulat ed histone genes in Drosophila hydei, we have found transcripts spanne d both histone H3 and H4 genes and were antisense for histone H3. As t he two histone genes are in opposite orientation, these transcripts co ntained the sense strand of the histone H4 gene. Such transcripts were present in both poly(A)(+) acid poly(A)(-) RNA fractions. The polyade nylated molecules contained a poly(A) tail at the 3' end of the stem-l oop structure, which is characteristic for cell-cycle regulated histon e mRNAs. The antisense RNA of histone H3 is synthesized exclusively in testes. By developing an improved protocol of in situ hybridization t o Drosophila testis squashes, we could demonstrate that the antisense transcripts are localized in the nuclei of primary spermatocytes. Poss ible functions of this RNA are discussed. (C) 1997 Wiley-Liss, Inc.