Aberrant Chromatin Remodeling by APL Fusion Proteins Assessed at the Single-Cell Level: Contribution of Reduced Mobility of Nuclear Coregulators

• Published in: Blood 2006-11, Vol.108 (11), p.2069-2069
• Main Authors: Tweardy, David John, Qui, Jihui, Huang, Ying, Dong, Shuo
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V108.11.2069.2069

Acute promyelocytic leukemia (APL) is notable for its specific t(15;17) chromosomal translocation-generated fusion protein, PML-RARα , and a dramatic clinical response to all-trans retinoic acid (ATRA) therapy. To explore the hypothesis that aberrant chromatin remodeling plays a role in PML-RARα-induced leukemogenesis and its reversal by ATRA at the single-cell level, we subcloned the open reading frames of wild type RARα , PML-RARα and PLZF-RARα into the amino-terminus of CFP-LacR. Immunoblot analysis, DNA binding studies, reporter assays and fluorescent microscopic analysis demonstrated that each CFP-LacR tagged construct encoded proteins of the expected size and that each gained the ability to bind to a Lac operator-containing reporter construct and activate transcription in an ATRA-dependent manner; addition of the tag did not interfere with their RARE binding ability or their cellular localization and distribution. Fluorescent microscopic examination of chromosomally integrated Lac operator arrays within the CHO cell line, A03_1, following expression of CFP-LacR-tagged proteins demonstrated that each of the tagged proteins localized to tightly packed arrays of less than half the volume of arrays within A03_1 cells transfected with CFP-LacR alone (p