Open AccessReplication forms of the gene-sized DNA molecules of hypotrichous ciliates.
Author(s) -
K G Murti,
David M. Prescott
Publication year - 1983
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.3.9.1562
Subject(s) - biology , dna , dna replication , molecule , gene , replication (statistics) , microbiology and biotechnology , genetics , virology , chemistry , organic chemistry
Using a method for obtaining DNA from 10 to 40 macronuclei for electron microscopy, we analyzed the structure of gene-sized, linear DNA molecules from S-phase macronuclei of two hypotrichous ciliates, Euplotes eurystomus and Styx sp. Three types of putative replicating intermediates were observed: (i) molecules with a bubble close to one end, (ii) molecules with single forks, and (iii) molecules with two forks. We conclude that: (i) each macronuclear DNA molecule replicates as an independent unit, (ii) the molecules contain an origin of replication close to one or both ends, and (iii) the mode of replication is bidirectional.