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The eclipse period of Escherichia coli
Author(s) -
von Freiesleben Ulrik,
Krekling Martin A.,
Hansen Flemming G.,
LøbnerOlesen Anders
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.22.6240
Subject(s) - eclipse , period (music) , escherichia coli , biology , astronomy , philosophy , physics , genetics , gene , aesthetics
The minimal time between successive initiations on the same origin (the eclipse) in Escherichia coli was determined to be ∼25–30 min. An inverse relationship was found between the length of the eclipse and the amount of Dam methyltransferase in the cell, indicating that the eclipse corresponds to the period of origin hemimethylation. The SeqA protein was absolutely required for the eclipse, and DnaA titration studies suggested that the SeqA protein prevented the binding of multiple DnaA molecules on oriC (initial complex formation). No correlation between the amount of SeqA and eclipse length was revealed, but increased SeqA levels affected chromosome partitioning and/or cell division. This was corroborated further by an aberrant nucleoid distribution in SeqA‐deficient cells. We suggest that the SeqA protein's role in maintaining the eclipse is tied to a function in chromosome organization.