Proteolysis of mitotic chromosomes induces gradual and anisotropic decondensation correlated with a reduction of elastic modulus and structural sensitivity to rarely cutting restriction enzymes

Lisa H. Pope, Chee Xiong, John F. Marko*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

The effect of nonspecific proteolysis on the structure of single isolated mitotic newt chromosomes was studied using chromosome elastic response as an assay. Exposure to either trypsin or proteinase K gradually decondensed and softened chromosomes but without entirely eliminating their elastic response. Analysis of chromosome morphology revealed anisotropic decondensation upon digestion, with length increasing more than width. Prolonged protease treatment resulted only in further swelling of the chromosome without complete dissolution. Mild trypsinization induced sensitivity of chromosome elasticity to five- and six-base-specific restriction enzymes. These results, combined with previous studies of effects of nucleases on mitotic chromosome structure, indicate that mild proteolysis gradually reduces the density of chromatin-constraining elements in the mitotic chromosome, providing evidence consistent with an anisotropically folded "chromatin network" model of mitotic chromosome architecture.

Original languageEnglish (US)
Pages (from-to)104-113
Number of pages10
JournalMolecular biology of the cell
Volume17
Issue number1
DOIs
StatePublished - Jan 2006

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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