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Injection of ecdysterone into mid-fourth instar larvae of Trichosia pubescens brought about drastic changes in the puffing pattern of the chromosomes of the salivary gland. The puff sequence induced by the hormone is quite similar to that which normally occurs at the end of larval life. Three classes of puffs were observed: the early induced, the late(More)
Trichosia pubescens larvae were ligated at different prepupal developmental stages in order to investigate whether ecdysterone acts just as a trigger or whether its presence in the hemolymph is constantly necessary for the induction of the late puffs, in particular the DNA puffs. The larvae were ligated in the middle of the body being sure that the salivary(More)
In the giant polytene chromosomes, gene amplification is made visible by formation of DNA puffs, and gene transcription is made visible by formation of RNA puffs. Ligation of the anterior portion of the larva at the end of the fourth larval instar inhibited the formation of the DNA puffs that normally develop at this stage and caused regression of RNA puffs.
The discovery of DNA sequence amplification in sciarid flies and investigations into its control and biological significance are reviewed. Results thus far show that amplification of specific salivary gland polytene chromosome bands is a general phenomenon in sciarids. It is brought about as part of a final endoreplication cycle by the rising titer of(More)
The antigens in HeLa andTrichosia pubescens cells, recognized by sera from patients with rheumatic diseases containing anti-Ku antibodies, were compared by means of immunoprecipitation of labeled cell extracts. The autoantibodies present in the tested sera precipitate at least two polypeptides of approximately Mr = 70000 and Mr = 80000 in HeLa cell extracts(More)
An antiserum (called AScE/D) against the semiconserved D-domain of a Chironomus tentans ecdysone receptor protein (cEcR) gave indirect immunofluorescence signals at DNA puff sites in Trichosia pubescens. The signals varied in maximum intensity at different DNA puff sites. Control experiments using the secondary rhodamine-labeled anti-rabbit IgG alone,(More)
During the course of experiments with larvae of Trichosia pubescens, we have unexpectedly found that diethyl ether or chloroform anesthesia induces a large puff in a specific band in the polytene chromosomes of the salivary glands. This puff develops a few minutes after the treatment, attaining its maximum size after 60-100 min, and regresses completely 200(More)
Antigens ofChironomus reactive with human sera containing anti-Ku antibodies and also with specific antibodies to each Ku subunit were characterized by immunoblot analysis. Three main antigen species were identified in nuclear-enriched extracts from salivary gland cells ofChironomus thummi, ranging in Mr from 55000 to 67000. The nuclear localization of(More)
Antibodies to specific nucleic acid conformations are amongst the methods that have allowed the study of non-canonical (Watson–Crick) DNA structures in higher organisms. In this work, the structural limitations for the immunological detection of DNA.RNA hybrid duplexes were examined using specific RNA homopolymers as probes for homopolymer polydeoxyadenylic(More)