Cytological localization of DNA complementary to ribosomal RNA in polytene chromosomes of Diptera

Pardue, Mary Lou; Gerbi, Susan A.; Eckhardt, Ronald A.; Gall, Joseph G.

doi:10.1007/bf00325943

Cited by 259 publications

(68 citation statements)

References 40 publications

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“…The rRNA genes are also underreplicated and dispersed in a network of filaments and granules within the nucleolus (Fig. 3a) as also found in Ceratitus capitata (Bedo & Webb, 1989) and Drosophyla hydei (Pardue et al, 1970). On the other hand, in Or.…”

Section: Ugandamentioning

confidence: 55%

Ribosomal RNA genes in mosquitoes: localization by fluorescence in situ hybridization (FISH)

Marchi

Pili

1994

Heredity

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Fluorescence in situ hybridization (FISH) was used to localize the 18S-28S ribosomal RNA gene clusters on the chromosomes of 15 mosquito species belonging to the Anophelinae and Culicinae subfamilies. In the genus Anopheles the rRNA genes are localized on the heterochromatic arm of both sex chromosomes. The association between rRNA genes and sex determining chromosomes also applies to the homomorphic karyotype of Culicinae mosquitoes, at least in those cases in which localization of the sex locus/loci has been determined. In these species ribosomal genes are often found within or adjacent to heterochromatic regions (C bands). Differences in the location of rRNA genes among and within genera suggest the occurrence of several chromosomal rearrangements during the evolution of mosquitoes.

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Section: Ugandamentioning

confidence: 55%

Ribosomal RNA genes in mosquitoes: localization by fluorescence in situ hybridization (FISH)

Marchi

Pili

1994

Heredity

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“…Unlike the satellite DNA, the rDNA replicates during the formation of polytene tissue. This has been demonstrated by thymidine incorporation in D. melanogaster (10,28), and by rRNA hybridization to DNA from salivary glands of D. hydei (11,12), Sciara (13), and Rhynchosciara (14).…”

mentioning

confidence: 92%

Independent Control of Ribosomal Gene Replication in Polytene Chromosomes of Drosophila melanogaster

Spear

Gall

1973

Proc. Natl. Acad. Sci. U.S.A.

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143

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The saturation values for ribosomal RNA hybridization have been determined for DNA from diploid and polytene tissues of Drosophila melanogaster. These values have been measured in XO and XX larvae which have, respectively, one and two nucleolus organizers in the diploid chromosome set. The results show that (1) in diploid cells the ribosomal (r)DNA is present in amounts proportional to the number of nucleolus organizers, (2) in polytene cells the rDNA is under-replicated with respect to the euchromatic DNA, and (3) in polytene cells the amount of rDNA is independent of the diploid number of nucleolus organizers. These observations suggest that somatic variations in rDNA content may involve independent polytenization of the nucleolus organizer without change in the number of ribosomal cistrons per organizer. The independent polytenization of rl)NA is proposed as the chromosomal explanation for the relative increase in rDNA in flies of the XO constitution.The chromosomes of Drosophila melanogaster, like those of most eukaryotes, contain two distinct types of chromatin, the euchromatin and the heterochromatin. The euchromatin is diffuse during interphase, is lightly staining in mitotic prophase, and contains almost all of the known genes (1). The heterochromatin, contrastingly, remains condensed during interphase, is consequently darkly staining in mitotic prophase, and contains very few genes. In addition to these genetic and cytological distinctions, the euchromatin consists mainly of unique DNA sequences, while most of the heterochromatin in diploid cells is highly repeated satellite DNA (2)(3)(4).During the formation of the giant polytene chromosomes of the Drosophila salivary gland, the differences between the euchromatin and heterochromatin become even more pronounced. The euchromatic arms proceed through a series of DNA replications resulting in as many as 1024 DNA fibers (5). The heterochromatic regions of the chromosomes, on the other hand, clump together forming the chromocenter and replicate little or not at all (2, 6). The resulting polytene nucleus has a large increase in unique DNA, but little or no increase in the heterochromatic satellite DNA (2, 7).In D. melanogaster the DNA that codes for ribosomal RNA is located at or near the nucleolus organizer, a region within the heterochromatin of the X and Y chromosomes (8). The ribosomal cistrons are repeated about 250 times in the nucleolus organizer of wild-type stocks (9). The properties of the ribosomal (r)DNA are quite different from those of the heterochromatic DNA that surrounds it. For instance, the rDNA is genetically active, transcribing rRNA and forming a prominent nucleolus in both diploid and polytene tissues. Unlike the satellite DNA, the rDNA replicates during the formation of polytene tissue. This has been demonstrated by thymidine incorporation in D. melanogaster (10, 28), and by rRNA hybridization to DNA from salivary glands of D. hydei (11, 12), Sciara (13), and Rhynchosciara (14).Because the rDNA in polytene nuclei is near the n...

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“…Such is also the case with the 5S r R N A cistrons, which are found clustered on one site (1, 9, 44), a few sites (9,39,42), or a large number of sites (30,31). Finally, the 18S + 28S R N A genes can be located on one (20,32) or several loci (17,42).…”

Section: Le6nmentioning

confidence: 76%

Molecular hybridization of iodinated 4S, 5S, and 18S + 28S RNA to salamander chromosomes.

León¹

1976

The Journal of Cell Biology

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4S, 5S, and 18S + 28S RNA from the newt Taricha granulosa granulosa were iodinated in vitro with carrier-free 125I and hybridized to the denatured chromosomes of Taricha granulosa and Batrachoseps wrighti. Iodinated 18S + 28S RNA hybridizes to the telomeric region on the shorter arm of chromosome 2 and close to the centromere on the shorter arm of chromosome 9 from T. granulosa. On this same salamander the label produced by the 5S RNA is located close to or on the centromere of chromosome 7 and the iodinated 4S RNA labels the distal end of the longer arm of chromosome 5. On the chromosomes of B. wrighti, 18S + 28S RNA hybridizes close to the centromeric region on the longer arm of the largest chromosome. Two centromeric sites are hybridized by the iodinated 5S RNA. After hybridization with iodinated 4S RNA, label is found near the end of the shorter arm of chromosome 3. It is concluded that both ribosomal and transfer RNA genes are clustered in the genome of these two salamanders.

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Cytological localization of DNA complementary to ribosomal RNA in polytene chromosomes of Diptera

Cited by 259 publications

References 40 publications

Ribosomal RNA genes in mosquitoes: localization by fluorescence in situ hybridization (FISH)

Ribosomal RNA genes in mosquitoes: localization by fluorescence in situ hybridization (FISH)

Independent Control of Ribosomal Gene Replication in Polytene Chromosomes of Drosophila melanogaster

Molecular hybridization of iodinated 4S, 5S, and 18S + 28S RNA to salamander chromosomes.

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