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Updated: Jul 18, 2026

Two- and Three-Dimensional Live Cell Imaging of DNA Damage Response Proteins
Published on: September 28, 2012
Parental expression of the chromodomain protein Pdd1p is required for completion of programmed DNA elimination and
R S Coyne1, M A Nikiforov, J F Smothers
1Department of Biology, Colgate University, Hamilton, New York 13346, USA. rcoyne@mail.colgate.edu
Abstract:
Thousands of DNA elimination events occur during somatic differentiation of many ciliated protozoa. In Tetrahymena, the eliminated DNA aggregates into submacronuclear structures containing the protein Pdd1p, a member of the chromodomain family. We disrupted somatic copies of PDD1, eliminating parental expression of the gene early in the sexual phase of the life cycle. Even though zygotic expression, from the undisrupted germline PDD1 copy, is activated before DNA elimination normally occurs, the somatic knockout cells suffer defects in DNA elimination, genome endoduplication, and nuclear resorption, and eventually die, demonstrating that PDD1 is essential and suggesting Pdd1p is directly involved in establishing a chromatin structure required for DNA elimination.
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