Stress response in Drosophila subobscura: DNA-RNA hybrids and transcriptional activity

• Published in: Biology of the cell Vol. 75; no. 3; p. 187
• Main Authors: Arbona, M, Cuenca, J B, de Frutos, R
• Format: Journal Article
• Language: English
• Published: England 1992
• Subjects: Animals; Chromosomes - chemistry; Chromosomes - ultrastructure; DNA - analysis; Drosophila - genetics; Drosophila - physiology; Fluorescent Antibody Technique; Gene Expression Regulation; Nucleic Acid Denaturation; Nucleic Acid Hybridization; RNA - analysis; RNA, Messenger - biosynthesis; Stress, Physiological - genetics; Stress, Physiological - physiopathology; Transcription, Genetic
• ISSN: 0248-4900
• DOI: 10.1016/0248-4900(92)90140-V

Immunofluorescent techniques have been used in the analysis of DNA-RNA hybrids occurrence and its relationship to transcriptional events on polytene chromosomes of Drosophila subobscura. We have studied the distribution of these hybrids on uninduced/induced chromosomes. Two different indirect immunofluorescence methods for the detection of DNA-RNA hybrids were used. Our data confirm the positive correlation between localization of DNA-RNA hybrids and transcriptional activity by following the Büsen et al procedure (1982). Using the other protocol, which allows chromosomal DNA-RNA to denature and renature, makes DNA-RNA hybrids detectable not exclusively in active chromosomal regions. Taking Büsen as method of choice, this technique allowed to localize the exact transcriptional active sites on puffs: hybrid fluorescence was restricted to marginal or central puff areas. Moreover, no correlation between fluorescence and puffs size was found. However, our studies on induced chromosomes indicate that: 1) the 15DE puff, previously described as t-puff, was not really a heat shock puff, since no transcriptional activity was detected; 2) hybrid fluorescence at 2C and 31CD regions was observed. No labelling was found in these loci in the autoradiography data, reported by other authors.