Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2009 Jun 29;185(7):1149–1157. doi: 10.1083/jcb.200810159

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2009 Tibelius et al.

This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.jcb.org/misc/terms.shtml). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).

PMC Copyright notice

Figure 5. — Down-regulation of MCPH1 induces premature entry into mitosis via depletion of centrosomal Chk1. (A and B) U2OS cells transfected with luciferase- (as control [siLUC]), MCPH1-, or PCNT-specific siRNA (A) as well as normal, MCPH1^427insA, and PCNT^3109G>T LBCs (B) were costained with propidium iodide and anti–P-S10–histone H3 and analyzed by fluorescence-activated cell sorting to quantify cells in mitosis. Statistical significance versus control by two-tailed Student's t test is as follows: (A) *, P = 0.02 (U2OS-siMCPH1); **, P = 0.001 (U2OS-siPCNT); (B) **, P = 0.009 (MCPH1^427insA); P = 0.09 (PCNT^3109G>T). (C) Parental U2OS cells or U2OS cells conditionally expressing wild-type (Chk1[WT]) or kinase-dead (Chk1[KD]) GFP-Chk1-PACT were transfected with MCPH1-specific siRNA and analyzed by fluorescence microscopy. The mean percentages of cells with PCC are indicated. Statistical significance versus Chk1(WT) by two-tailed Student's t test is as follows: ***, P = 0.0008 (U2OS); P = 0.0002 (Chk1[KD]). (D) Characterization of the PCC phenotype. U2OS cells were transfected with luciferase- or MCPH1-specific siRNA and immunostained with antibodies to cyclin B1 (top), lamin A (middle), and P-S10–histone H3 (pH3; bottom). DNA was counterstained with To-Pro 3. After transfection with MCPH1-specific siRNA, PCC cells have an intact nuclear membrane as judged by lamin A staining, are P-S10–histone H3 negative, and show no nuclear cyclin B1 accumulation, thereby demonstrating that they exhibit G₂ rather than mitotic characteristics. Error bars represent the standard deviation after combining the results of three different experiments. Bars, 10 µm.