Resting cells rely on the DNA helicase component MCM2 to build cilia

Nucleic Acids Res. 2019 Jan 10;47(1):134-151. doi: 10.1093/nar/gky945.

Abstract

Minichromosome maintenance (MCM) proteins facilitate replication by licensing origins and unwinding the DNA double strand. Interestingly, the number of MCM hexamers greatly exceeds the number of firing origins suggesting additional roles of MCMs. Here we show a hitherto unanticipated function of MCM2 in cilia formation in human cells and zebrafish that is uncoupled from replication. Zebrafish depleted of MCM2 develop ciliopathy-phenotypes including microcephaly and aberrant heart looping due to malformed cilia. In non-cycling human fibroblasts, loss of MCM2 promotes transcription of a subset of genes, which cause cilia shortening and centriole overduplication. Chromatin immunoprecipitation experiments show that MCM2 binds to transcription start sites of cilia inhibiting genes. We propose that such binding may block RNA polymerase II-mediated transcription. Depletion of a second MCM (MCM7), which functions in complex with MCM2 during its canonical functions, reveals an overlapping cilia-deficiency phenotype likely unconnected to replication, although MCM7 appears to regulate a distinct subset of genes and pathways. Our data suggests that MCM2 and 7 exert a role in ciliogenesis in post-mitotic tissues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cilia / genetics*
  • Cilia / pathology
  • Ciliopathies / genetics
  • Ciliopathies / pathology
  • DNA Helicases / genetics*
  • Humans
  • Minichromosome Maintenance Complex Component 2 / genetics*
  • Minichromosome Maintenance Complex Component 7 / genetics*
  • Mitosis / genetics
  • Transcription Initiation Site
  • Transcription, Genetic*
  • Zebrafish / genetics

Substances

  • DNA Helicases
  • MCM2 protein, human
  • MCM7 protein, human
  • Minichromosome Maintenance Complex Component 2
  • Minichromosome Maintenance Complex Component 7