Fanconi anemia signaling network regulates the spindle assembly checkpoint
Grzegorz Nalepa, … , Helmut Hanenberg, D. Wade Clapp
Grzegorz Nalepa, … , Helmut Hanenberg, D. Wade Clapp
Published August 15, 2013
Citation Information: J Clin Invest. 2013;123(9):3839-3847. https://doi.org/10.1172/JCI67364.
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Research Article Hematology

Fanconi anemia signaling network regulates the spindle assembly checkpoint

Abstract

Fanconi anemia (FA) is a heterogenous genetic disease with a high risk of cancer. The FA proteins are essential for interphase DNA damage repair; however, it is incompletely understood why FA-deficient cells also develop gross aneuploidy, leading to cancer. Here, we systematically evaluated the role of the FA proteins in chromosome segregation through functional RNAi screens and analysis of primary cells from patients with FA. We found that FA signaling is essential for the spindle assembly checkpoint and is therefore required for high-fidelity chromosome segregation and prevention of aneuploidy. Furthermore, we discovered that FA proteins differentially localize to key structures of the mitotic apparatus in a cell cycle–dependent manner. The essential role of the FA pathway in mitosis offers a mechanistic explanation for the aneuploidy and malignant transformation known to occur after disruption of FA signaling. Collectively, our findings provide insight into the genetically unstable cancers resulting from inactivation of the FA/BRCA pathway.

Authors

Grzegorz Nalepa, Rikki Enzor, Zejin Sun, Christophe Marchal, Su-Jung Park, Yanzhu Yang, Laura Tedeschi, Stephanie Kelich, Helmut Hanenberg, D. Wade Clapp

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Figure 3

Spindle checkpoint failure in primary human FA cells.

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Spindle checkpoint failure in primary human FA cells. (A) Experiment sch...
(A) Experiment schematic. (B) FA fibroblasts fail to arrest in mitosis upon taxol exposure and generate multinucleated cells (arrows). Original magnification, ×200 (Applied Precision personalDX). (C) Quantification of SAC defects in cells from patients with FA. *P < 0.01 (1-way ANOVA with post-hoc Bonferroni’s correction); n = 10–15 counts per genotype. (D) Ectopic expression of FANCA rescues the SAC defect in FA-A fibroblasts exposed to taxol. *P = 0.0038 (2-tailed t test); n = 15 counts. (E) FANCA-deficient patient fibroblasts fail to arrest at the SAC in response to nocodazole. *P = 0.021 (2-tailed t test); n = 15 counts. All bars represent mean values ± SEM.