Microcephalin 1/BRIT1-TRF2 interaction promotes telomere replication and repair, linking telomere dysfunction to

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Alessandro Cicconi1, Rekha Rai1, Xuexue Xiong2

  • 1Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT, 06520, USA.

Nature Communications
|November 18, 2020
PubMed

Insights

Microcephaly is linked to telomere dysfunction. This study reveals microcephalin 1 (MCPH1) protein interacts with TRF2, promoting telomere replication and DNA repair, suggesting replication defects contribute to microcephaly.

Area of Science:

  • Genetics
  • Molecular Biology
  • Cell Biology

Background:

  • Telomeres protect chromosome ends from DNA damage.
  • Primary microcephaly is a symptom of telomere disorders, but the link is unclear.
  • The microcephalin 1 (MCPH1) gene is mutated in primary microcephaly.

Purpose of the Study:

  • To investigate the molecular link between MCPH1, telomeres, and microcephaly.
  • To elucidate the role of MCPH1 in telomere maintenance and replication.
  • To understand how MCPH1 dysfunction contributes to primary microcephaly.

Main Methods:

  • Co-immunoprecipitation to detect protein interactions.
  • Crystal structure analysis of the MCPH1-TRF2 complex.
  • Analysis of DNA damage factor recruitment and telomere repair.
  • Assessment of telomere replication fork progression and restart.

Main Results:

  • MCPH1 directly interacts with the TRFH domain of TRF2 via its YRLSP motif.
  • MCPH1 facilitates the recruitment of DNA damage factors to dysfunctional telomeres.
  • MCPH1 promotes homology-directed repair of telomeres lacking POT1-TPP1.
  • MCPH1 is crucial for telomere replication fork progression and restart during replication stress.

Conclusions:

  • MCPH1 plays a vital role in telomere replication and repair.
  • Dysfunctional telomere replication due to MCPH1 defects may cause primary microcephaly.
  • This study uncovers a novel function of MCPH1 in maintaining telomere integrity.

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