A regulatory effect of INMAP on centromere proteins: antisense INMAP induces CENP-B variation and centromeric halo

PLoS One. 2014 Mar 14;9(3):e91937. doi: 10.1371/journal.pone.0091937. eCollection 2014.

Abstract

CENP-B is a highly conserved protein that facilitates the assembly of specific centromere structures both in interphase nuclei and on mitotic chromosomes. INMAP is a conserved protein that localizes at nucleus in interphase cells and at mitotic apparatus in mitotic cells. Our previous results showed that INMAP over-expression leads to spindle defects, mitotic arrest and formation of polycentrosomal and multinuclear cells, indicating that INMAP may modulate the function of (a) key protein(s) in mitotic apparatus. In this study, we demonstrate that INMAP interacts with CENP-B and promotes cleavage of the N-terminal DNA binding domain from CENP-B. The cleaved CENP-B cannot associate with centromeres and thus lose its centromere-related functions. Consistent with these results, CENP-B in INMAP knockdown cells becomes more diffused around kinetochores. Although INMAP knockdown cells do not exhibit gross defects in mitotic spindle formation, these cells go through mitosis, especially prophase and metaphase, with different relative timing, indicating subtle abnormality. These results identify INMAP as a model regulator of CENP-B and support the notion that INMAP regulates mitosis through modulating CENP-B-mediated centromere organization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Cell Cycle Proteins / deficiency
  • Cell Cycle Proteins / genetics*
  • Cell Cycle Proteins / metabolism*
  • Centromere / metabolism*
  • Centromere Protein B / chemistry
  • Centromere Protein B / metabolism*
  • DNA / metabolism
  • Gene Knockdown Techniques*
  • HeLa Cells
  • Humans
  • Nuclear Proteins / deficiency
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • Proteolysis

Substances

  • Cell Cycle Proteins
  • Centromere Protein B
  • INMAP protein, human
  • Nuclear Proteins
  • DNA

Grants and funding

This study was supported by the National Natural Science Foundation of China (no. 30971470 to QL), the Beijing Natural Science Foundation (no. 5122017 to QL), the open fund of Key Laboratory of Cell Proliferation and Regulation Biology, the Ministry of Education (no. 201001 to YZ) and the open fund of Beijing Key Laboratory of Gene Resource and Molecular Development (no. 201102 to YZ and no. 201204 YZ). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.