HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE ADVANCED SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Morigen Articles by Skarstad, K. Search for Related Content PubMed Articles by Morigen, Articles by Skarstad, K.

Department of Cell Biology, Institute for Cancer Research, Norwegian Radium Hospital, Rikshospitalet, University of Oslo, 0310 Oslo, Norway

When the bacterium Escherichia coli is grown in rich medium, the replication and segregation periods may span two, three or four generations and cells may contain up to 24 replication forks. The newly synthesized, hemimethylated DNA at each fork is bound by SeqA protein. The SeqA–DNA structures form distinct foci that can be observed by immunofluorescence microscopy. The numbers of foci were lower than the numbers of replication forks indicating fork co-localization. The extent of co-localization correlated with the extent of replication cycle overlap in wild-type cells. No abrupt increase in the numbers of foci occurred at the time of initiation of replication, suggesting that new replication forks bind to existing SeqA structures. Manipulations with replication control mechanisms that led to extension or reduction of the replication period and number of forks, did not lead to changes in the numbers of SeqA foci per cell. The results indicate that the number of SeqA foci is not directly governed by the number of replication forks, and supports the idea that new DNA may be ‘captured’ by existing SeqA structures.

^* Correspondence: kirsten.skarstad{at}rr-research.no