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Updated: Aug 7, 2026

Preparation of Drosophila Polytene Chromosome Squashes for Antibody Labeling
Published on: February 9, 2010
Chromatin loosening by poly(ADP)-ribose polymerase (PARP) at Drosophila puff loci
Alexei Tulin1, Allan Spradling
1Howard Hughes Medical Research Laboratories, Embryology Department, Carnegie Institution of Washington, 115 West University Parkway, Baltimore, MD 21210, USA.
Abstract:
Steroid response and stress-activated genes such as hsp70 undergo puffing in Drosophila larval salivary glands, a local loosening of polytene chromatin structure associated with gene induction. We find that puffs acquire elevated levels of adenosine diphosphate (ADP)-ribose modified proteins and that poly(ADP)-ribose polymerase (PARP) is required to produce normal-sized puffs and normal amounts of Hsp70 after heat exposure. We propose that chromosomal PARP molecules become activated by developmental or environmental cues and strip nearby chromatin proteins off DNA to generate a puff. Such local loosening may facilitate transcription and may transiently make protein complexes more accessible to modification, promoting chromatin remodeling during development.
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