Four-dimensional imaging of E. coli nucleoid organization and dynamics in living cells.
Cell
; 153(4): 882-95, 2013 May 09.
Article
en En
| MEDLINE
| ID: mdl-23623305
ABSTRACT
Visualization of living E. coli nucleoids, defined by HupA-mCherry, reveals a discrete, dynamic helical ellipsoid. Three basic features emerge. (1) Nucleoid density coalesces into longitudinal bundles, giving a stiff, low-DNA-density ellipsoid. (2) This ellipsoid is radially confined within the cell cylinder. Radial confinement gives helical shape and directs global nucleoid dynamics, including sister segregation. (3) Longitudinal density waves flux back and forth along the nucleoid, with 5%-10% of density shifting within 5 s, enhancing internal nucleoid mobility. Furthermore, sisters separate end-to-end in sequential discontinuous pulses, each elongating the nucleoid by 5%-15%. Pulses occur at 20 min intervals, at defined cell-cycle times. This progression includes sequential installation and release of programmed tethers, implying cyclic accumulation and relief of intranucleoid mechanical stress. These effects could comprise a chromosome-based cell-cycle engine. Overall, the presented results suggest a general conceptual framework for bacterial nucleoid morphogenesis and dynamics.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Cromosomas Bacterianos
/
Escherichia coli
Idioma:
En
Año:
2013
Tipo del documento:
Article