Cytological localization of ribosomal cistrons in polytene chromosomes of Phaseolus coccineus

Chromosoma ◽  
1972 ◽  
Vol 39 (2) ◽  
pp. 191-203 ◽  
Author(s):  
S. Avanzi ◽  
M. Durante ◽  
P. G. Cionini ◽  
F. D'Amato
Keyword(s):  
Polytene Chromosomes ◽  
Phaseolus Coccineus ◽  
Ribosomal Cistrons ◽  
Cytological Localization

Detection of rRNA and phaseolin genes on polytene chromosomes of Phaseolus coccineus by fluorescence in situ hybridization after pepsin pretreatment

Genome ◽  
1994 ◽  
Vol 37 (6) ◽  
pp. 1018-1021 ◽  
Author(s):  
M. Nenno ◽  
K. Schumann ◽  
W. Nagl
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Ribosomal Rna ◽  
Storage Protein ◽  
Seed Storage Protein ◽  
Polytene Chromosomes ◽  
Seed Storage ◽  
Phaseolus Coccineus ◽  
Rna Genes

This is the first report of fluorescence in situ hybridization (FISH) on plant polytene chromosomes. Different protease pretreatments have been tested to improve fluorescence in situ hybridization FISH on polytene chromosomes of a plant, Phaseolus coccineus, with the aim to enable the detection of low-copy genes. The structural preservation of the chromosomes and the distinctness of the FISH signals were comparatively analysed with a probe for the ribosomal RNA genes after digestion with pepsin and trypsin. The pepsin pretreatment resulted in a general loosening of chromatin with good conservation of chromosome morphology and an increased number and density of signal points. The six nucleolus organizers exhibited significant differences in condensation. The pretreatment with pepsin enabled the detection of the low-copy genes encoding the seed storage protein phaseolin.Key words: plant, Leguminosae, ribosomal RNA genes, seed storage protein genes, protease.

scholarly journals UNDER-REPLICATION OF RIBOSOMAL CISTRONS IN POLYTENE CHROMOSOMES OF RHYNCHOSCIARA

1974 ◽  
Vol 62 (1) ◽  
pp. 215-222 ◽  
Author(s):  
A. G. Gambarini ◽  
F. J. S. Lara
Keyword(s):  
Salivary Gland ◽  
In Situ Hybridization ◽  
Xenopus Laevis ◽  
Related Species ◽  
Polytene Chromosomes ◽  
Chromosome X ◽  
Heterologous Hybridization ◽  
Ribosomal Cistrons ◽  
Rhynchosciara Americana

DNA preparations obtained from several tissues of Rhynchosciara americana and two related species, R. milleri and R. papaveroi, were hybridized to R. americana rRNA. The percentage of hybridization was found to be higher in tissues with low polyteny than in tissues with high polyteny, suggesting a relationship between the amount of rDNA and the tissue polyteny. This could be explained by under-replication of ribosomal cistrons in polytene cells, such as those from the salivary gland. Only slight tissue-dependent changes in the percentages of hybridization can be observed in heterologous hybridization using Xenopus laevis rRNA. The possibility that these experiments could not detect differences in the amount of ribosomal cistrons among tissues is discussed. The female:male ratio for the percentages of hybridization in the salivary gland of R. americana agrees with the results obtained by in situ hybridization experiments (16, 17) which have shown that the rRNA cistrons are distributed among chromosomes other than chromosome X.

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