Dependence of the structure and mechanics of metaphase chromosomes on oxidized cysteines.
Chromosome Res
; 24(3): 339-53, 2016 09.
Article
de En
| MEDLINE
| ID: mdl-27145786
ABSTRACT
We have found that reagents that reduce oxidized cysteines lead to destabilization of metaphase chromosome folding, suggesting that chemically linked cysteine residues may play a structural role in mitotic chromosome organization, in accord with classical studies by Dounce et al. (J Theor Biol 42275-285, 1973) and Sumner (J Cell Sci 70177-188, 1984a). Human chromosomes isolated into buffer unfold when exposed to dithiothreitol (DTT) or tris(2-carboxyethyl)phosphine (TCEP). In micromanipulation experiments which allow us to examine the mechanics of individual metaphase chromosomes, we have found that the gel-like elastic stiffness of native metaphase chromosomes is dramatically suppressed by DTT and TCEP, even before the chromosomes become appreciably unfolded. We also report protein labeling experiments on human metaphase chromosomes which allow us to tag oxidized and reduction-sensitive cysteine residues. PAGE analysis using fluorescent labels shows a small number of labeled bands. Mass spectrometry analysis of similarly labeled proteins provides a list of candidates for proteins with oxidized cysteines involved in chromosome organization, notably including components of condensin I, cohesin, the nucleosome-interacting proteins RCC1 and RCC2, as well as the RNA/DNA-binding protein NONO/p54NRB.
Mots clés
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Protéines chromosomiques nonhistones
/
Chromosomes humains
/
Cystéine
/
Métaphase
Limites:
Animals
/
Humans
Langue:
En
Journal:
Chromosome Res
Sujet du journal:
BIOLOGIA MOLECULAR
Année:
2016
Type de document:
Article
Pays d'affiliation:
États-Unis d'Amérique