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Polytene chromosome

About: Polytene chromosome is a(n) research topic. Over the lifetime, 2667 publication(s) have been published within this topic receiving 88255 citation(s).
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Journal ArticleDOI
TL;DR: The salivary glands and other tissues from Drosophila melanogaster were dissected at various times throughout the prepupal period, as well as after heat shocks and ecdysterone treatments, and the proteins labelled by incubating the isolated tissues with [35S]methionine were separated by electrophoresis on sodium dodecyl sulphate-polyacrylamide gel.
Abstract: The salivary glands and other tissues from Drosophila melanogaster were dissected at various times throughout the prepupal period, as well as after heat shocks and ecdysterone treatments, and the proteins labelled by incubating the isolated tissues with [35S]methionine were separated by electrophoresis on sodium dodecyl sulphate-polyacrylamide gel. The labelled band patterns from salivary gland, as seen on the autoradiograph of the gel, showed striking variations, in a manner remarkably similar to variations in puff patterns during the same prepupal period. In proteins from Malpighian tubes, the pattern of bands varied to a lesser extent and in brain only a few components were modified. Heat shock brought about the appearance of a number of new bands, while others were reduced in intensity. This effect was observed with all the tissues examined, salivary glands, brain and Malpighian tubes, as well as wing imaginal discs, tissue lacking polytene chromosomes. The six most heavily labelled bands induced by heat shock represent about 30%, and one component alone represents over 15%, of the total label in the sample, as seen in salivary glands, brain and Malpighian tubes. The synthesis of RNA at puff sites was investigated after heat shock by [3H]uridine labelling. By correlating the amount of [3H]uridine in some puffs with the level of [35S]methionine in some bands a tentative relation is suggested in a few instances. The effect of ecdysterone treatment was also studied in the salivary glands. Changes in a number of protein bands were noticed, though they were much less pronounced than those following heat shock.

1,119 citations


Journal ArticleDOI
TL;DR: This immunological approach offers four advantages over conventional autoradiographic procedures for detecting in situ hybrids: the time required to determine the site of hybridization is decreased markedly, the biotin-labeled probes are chemically stable and give reproducible results for many months, and the resolving power is equal to and often greater than that achievedautoradiographically.
Abstract: A method is described for localizing DNA sequences hybridized in situ to Drosophila polytene chromosomes. This procedure utilizes a biotin-labeled analog of TTP that can be incorporated enzymatically into DNA probes by nick-translation. After hybridization in situ, the biotin molecules in the probe serve as antigens which bind affinity-purified rabbit antibiotin antibodies. The site of hybridization is then detected either fluorimetrically, by using fluorescein-labeled goat anti-rabbit IgG, or cytochemically, by using an anti-rabbit IgG antibody conjugated to horseradish peroxidase. When combined with Giemsa staining, the immunoperoxidase detection method provides a permanent record that is suitable for detailed cytogenetic analysis. This immunological approach offers four advantages over conventional autoradiographic procedures for detecting in situ hybrids: (i) the time required to determine the site of hybridization is decreased markedly, (ii) biotin-labeled probes are chemically stable and give reproducible results for many months; (iii) biotin-labeled probes appear to produce less background noise than do radiolabeled probes; and (iv) the resolving power is equal to and often greater than that achieved autoradiographically.

706 citations




Journal ArticleDOI
29 Jul 1988-Cell
TL;DR: Amino acid sequencing of the purified peptide and oligonucleotide-directed cDNA cloning established that the peptide consists of 36 amino acids, and appears to be synthesized as a precursor with a hydrophobic signal sequence of 19 residues at its N-terminal end.
Abstract: The adult male accessory glands of D. melanogaster synthesize and secrete a peptide that represses female sexual receptivity and stimulates oviposition. Normally, this peptide is transferred to females during copulation; however, the peptide shows the same biological activity after purification and subsequent injection into the adbominal cavity of female virgins. Amino acid sequencing of the purified peptide and oligonucleotide-directed cDNA cloning established that the peptide consists of 36 amino acids. It appears to be synthesized as a precursor with a hydrophobic signal sequence of 19 residues at its N-terminal end. The precursor peptide is encoded by a short mRNA that accumulates exclusively in the male accessory gland. The gene has been localized by in situ hybridization to polytene chromosomes at 70A.

580 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202116
202012
201916
201818
201722
201632

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Topic's top 5 most impactful authors

Igor F. Zhimulev

116 papers, 2.5K citations

Elena S. Belyaeva

62 papers, 1.7K citations

Paraskeva Michailova

23 papers, 214 citations

Galina V. Pokholkova

19 papers, 340 citations

V. F. Semeshin

19 papers, 249 citations