Arrangements and rearrangements of sequences flanking the two types of rDNA insertion in D. melanogaster

Roiha, Heli; Miller, J. Ross; Woods, Lesley C.; Glover, David M.

doi:10.1038/290749a0

Cited by 183 publications

(148 citation statements)

References 33 publications

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“…There are, however, a high proportion of rDNA units which contain insertion sequences in their 28S rRNA genes and which are transcribed at very low levels (13). rDNA containing the major type I insertion are incapable of producing functional rRNA since they have a deletion of part of the 28S gene flanking the insertion (14). Transcripts homologous to part of the insertion can however be detected in the cytoplasm.…”

Section: Resultsmentioning

confidence: 99%

Transcription of the ‘non-transcribed’ spacer ofDrosophila melanogasterrDNA

1983

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We have detected a set of transcripts in Drosophila melanogaster cells which are homologous to repeating elements within the 'non-transcribed' spacer region of rDNA. The RNA molecules range from 240 to 1680 nucleotides, differing in length by an integral value of 240 nucleotides. We have sequenced several AluI fragments which characterise the main 240 nucleotide repeating element. We find that each of these fragments contain a segment of approximately 50 nucleotides,which is homologous to the transcription initiation site for pre-rRNA.

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Section: Resultsmentioning

confidence: 99%

Transcription of the ‘non-transcribed’ spacer ofDrosophila melanogasterrDNA

1983

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“…The nomenclature used to describe the chromosome morphology was based on Levan et al (1964). The C-banding was performed using Sumner's technique (1972), with slight modifications to allow the localization of constitutive heterochromatic regions, and fluorescent in situ hybridization (FISH) was performed in mitotic and/or meiotic cells using a rDNA probe (pDm 238: recombinant plasmid with a 11,5 kb fragment corresponding to the rDNA repetitive unit of D. melanogaster, inserted in the Eco RI site of the pBR 322 plasmid (Roiha et al, 1981)). The FISH procedure was done as described in Parise-Maltempi and Avancini (2000).…”

Section: Chromosome Analysismentioning

confidence: 99%

Comparative cytogenetic study in Muscidae flies

Parise-Maltempi

Avancini

2007

Braz. J. Biol.

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The chromosome modal number in Muscoidea Diptera is 2n = 12, including five pairs of autosomes and one sex chromosome pair. Nevertheless, some species with 2n = 10 chromosomes have been described, all of them from the Muscidae family. We analyzed the karyotype of some Muscidae species from different subfamilies and compared the obtained data with the karyotypes of some species of the families Calliphoridae and Sarcophagidae. Comparisons of these species with other Muscidae species revealed a considerable variation among their sex chromosomes. This variation in the length of the sex chromosomes suggests that parts of these chromosomes were lost or fused with autosomes. The constitutive heterochromatic regions and the nucleolar organizer regions (NORs) were also analyzed and some aspects about the relationship between these regions and the sex chromosomes are discussed.Keywords: Muscidae, cytogenetics, sex chromosomes, heterochromatin, FISH. Estudo citogenético comparativo em moscas da família MuscidaeResumo O número modal de cromossomos dos Dípteros Muscóideos é 2n = 12, incluindo cinco pares de autossomos e um par de cromossomos sexuais. No entanto, algumas espécies com 2n = 10 cromossomos já foram descritas, sendo todas pertencentes à família Muscidae. No presente trabalho, foram analisados os cariótipos de algumas espécies de Muscidae de diferentes subfamílias e os dados obtidos foram comparados com os cariótipos de algumas espécies das famílias Calliphoridae e Sarcophagidae. Comparações destas espécies com outras da família Muscidae revelaram uma considerável variação entre seus cromossomos sexuais. Esta variação no tamanho dos cromossomos sexuais sugere que parte destes cromossomos foram perdidos ou sofreram fusão com autossomos. As regiões de heterocromatina constitutiva e as regiões organizadoras de nucléolos (RONs) foram também analisadas e alguns aspectos sobre a relação destas com os cromossomos sexuais são discutidos.

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“…The ribosomal probe used was pDm238 (Roiha et a!., 1981) cloned in pBR322. It contains the 18S, 5.8S, 28S genes, plus intergenic spacers of Drosophila melanogaster.…”

Section: Dna Probementioning

confidence: 99%

Localization and activity of rDNA genes in tiger beetles (Coleoptera: Cicindelinae)

et al. 1995

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Silver staining of male meiotic nuclei of six species of the tiger beetle genus Cicindela (tribe Cicindelini), with multiple sex chromosomes, reveals the presence of active nucleolar organizing regions (NORs) in the sex vesicle. In one species, Cicindela melancholica, fluorescence in situ hybridization (FISH) with a ribosomal probe showed that rDNA genes are in one of the three X chromosomes and in the Y chromosome. Silver staining and FISH show that the related species Cicindela paludosa with a male XO system, has NORs located in one pair of autosomes. In Megacephala euphratica (tribe Megacephalini) these techniques indicate that NORs are located in three autosomal pairs but not in the single X chromosome of males. In all these species the nucleolus can be seen from the onset of meiosis to the end of the diffuse stage; it disappears from diplotene to the end of meiosis and appears again during the spermatid stage. From these results it is concluded that: (i) the nucleolus does not seem to play a major role in the pairing and association of the multiple sex chromosomes during first meiotic prophase and metaphase; (ii) the occurrence of NORs in the heterosomes of species having multiple sex chromosomes is thought to be an ancestral condition for the genus Cicindela; and (iii) changes of location of NORs from the heterosomes to the autosomes have occurred within species of this genus, at least in species showing extensive karyotypic repatterning.

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Arrangements and rearrangements of sequences flanking the two types of rDNA insertion in D. melanogaster

Cited by 183 publications

References 33 publications

Transcription of the ‘non-transcribed’ spacer ofDrosophila melanogasterrDNA

Transcription of the ‘non-transcribed’ spacer ofDrosophila melanogasterrDNA

Comparative cytogenetic study in Muscidae flies

Localization and activity of rDNA genes in tiger beetles (Coleoptera: Cicindelinae)

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