Quantitative proteomics of the mitotic chromosome scaffold reveals the association of BAZ1B with chromosomal axes

Shinya Ohta*, Takako Taniguchi, Nobuko Sato, Mayako Hamada, Hisaaki Taniguchi, Juri Rappsilber

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

In mitosis, chromosomes achieve their characteristic shape through condensation, an essential process for proper segregation of the genome during cell division. A classical model for mitotic chromosome condensation proposes that non-histone proteins act as a structural framework called the chromosome scaffold. The components of the chromosome scaffold, such as DNA topoisomerase II (TOP2A) and structural maintenance of chromosomes protein 2 (SMC2), are necessary to generate stable mitotic chromosomes; however, the existence of this scaffold remains controversial. The aim of this study was to determine the protein composition of the chromosome scaffold. We used the DT40 chicken cell line to isolate mitotic chromosomes and extract the associated protein fraction, which could contain the chromosome scaffold. MS revealed a novel component of the chromosome scaffold, bromodomain adjacent to zinc finger 1B (BAZ1B), which was localized to the mitotic chromosome axis. Knocking out BAZ1B caused prophase delay because of altered chromosome condensation timing and mitosis progression errors, and the effect was aggravated if BAZ1A, a BAZ1B homolog, was simultaneously knocked out; however, protein composition of prometaphase chromosomes was normal. Our results suggest that BAZ1 proteins are essential for timely chromosome condensation at mitosis entry. Further characterization of the functional role of BAZ1 proteins would provide new insights into the timing of chromosome condensation.

Original languageEnglish
Pages (from-to)169-181
Number of pages13
JournalMolecular & Cellular Proteomics (MCP)
Volume18
Issue number2
Early online date28 Sept 2018
DOIs
Publication statusPublished - 1 Feb 2019

Keywords / Materials (for Non-textual outputs)

  • Cell Biology
  • Cell Cycle
  • Cell Division
  • Chromatin Function or Biology
  • Chromosome
  • Mitosis
  • SILAC

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