Ribosomal DNA-related sequences in a Y chromosomal lampbrush loop of Drosophila hydei

Degenerating gypsy retrotransposons in a male fertility gene on the Y chromosome of Drosophila hydei

“…Transcribed Y-specific repeats of D. hydei, such as ay 1, are present only in the closely related species D. neohydei and D. eohydei (Vogt et al 1986;Hareven et al 1986;Wlaschek et al 1988). Rally repeats, which are transcribed in the Threads" and Pseudonucleolus, are found exclusively in D. hydei (Huijser and Hennig 1987). Micropia elements, which in D. hydei are transcribed in these loop pairs as well , are found in only a few copies on the Y chromosome of D. melanogaster , and they are not transcribed in any of the lampbrush loop pairs of this species (S. Lankenau et al 1994).…”

“…On the contrary, our studies of the molecular composition of these genes have revealed that the DNA transcribed in the loops consists of two major types of repetitive sequences (Vogt et al 1982;Hennig et al 1983;Hennig 1983, 1986a,b;Huijser and Hennig 1987;Huijser et al 1988;Hochstenbach et al 1993a). The first type is satellite-like Y-specific DNA sequences without protein-coding capacity that have also been studied by others (Lifschytz et al 1983;Wlaschek et al 1988;Trapitz et al 1988Trapitz et al , 1992.…”

Strukturdifferenzierungen in Y-Chromosom vonDrosophila hydei: The unique morphology of the Y chromosomal lampbrush loopsThreads results from ‘coaxial shells’ formed by different satellite-specific subregions within megabase-sized transcripts

“…Remarkably, the original green colour of the fluorescein-labelled rally probe is restricted to the NO region. This NO-specific labelling reflects the extensive homology between rally-related and ribosomal RNA sequences (Huijser & Hennig 1987). Thus, the yellow colour for blocks of rally-specific transcripts along the Threads is indicative of almost perfect mixing or masking of green-coloured rally transcripts by redcoloured Texas red-labelled YLI-specific transcripts originating in the red-coloured distal block of these repeats.…”

“…The mutant stocks kept were as follows: Transcript in sito hybridizations Nuclei of primary spermatocytes of D. hydei were prepared exactly as described previously (G1/itzer 1984). In situ hybridizations on the transcripts of Y chromosomal lampbrush loops were performed according to Trapitz et al (1988) with fluorescein-and/or digoxigenin-labelled RNA and/or DNA samples prepared by in vitro transcription and/or oligo-labelling from the YLI-and YLII-specific clones pSP64 HR 17/9.2 and pSP64 HR 11/2.2 respectively , and the rally-specific plasmid pDhMiPi14.1 (Huijser & Hennig 1987) or corresponding Bluescript phagemid (Stratagene) subclones. Detection of biotinylated probes were performed by incubation with rabbit anti-biotin antibody (ENZO) and fluorescein isothiocyanate (FITC)-conjugated F(ab')2 fragment of goat anti-rabbit IgG (Dianova) as a secondary antibody.…”

“…Owing to their insensitivity to specific restriction enzymes, clusters of repetitive sequences can easily be identified and separated from non-repetitive stretches of normally digestable DNA by PFGE. Since most pieces in our hands were from the Threads puzzle, we decided to determine the long-range organization and mode of transcription along this loop: (Huijser & Hennig 1987, Trapitz et al 1988). 2.…”