TY - JOUR
T1 - Kinetoplast maxicircle DNA replication in Crithidia fasciculata and Trypanosoma brucei
AU - Carpenter, Laura Rocco
AU - Englund, Paul T.
PY - 1995/12
Y1 - 1995/12
N2 - Kinetoplast DNA, the mitochondrial DNA of trypanosomatids, is composed of several thousand minicircles and a few dozen maxicircles, all of which are topologically interlocked in a giant network. We have studied the replication of maxicircle DNA, using electron microscopy to analyze replication intermediates from both Crithidia fasciculata and Trypanosoma brucei. Replication intermediates were stabilized against branch migration by introducing DNA interstrand cross-links in vivo with 4,5',8- trimethylpsoralen and UV radiation. Electron microscopy of individual maxicircles resulting from a topoisomerase II decatenation of kinetoplast DNA networks revealed intact maxicircle θ structures. Analysis of maxicircle DNA linearized by restriction enzyme cleavage revealed branched replication intermediates derived from θ structures. Measurements of the linearized branched molecules in both parasites indicate that replication initiates in the variable region (a noncoding segment characterized by repetitive sequences) and proceeds unidirectionally, clockwise on the standard map.
AB - Kinetoplast DNA, the mitochondrial DNA of trypanosomatids, is composed of several thousand minicircles and a few dozen maxicircles, all of which are topologically interlocked in a giant network. We have studied the replication of maxicircle DNA, using electron microscopy to analyze replication intermediates from both Crithidia fasciculata and Trypanosoma brucei. Replication intermediates were stabilized against branch migration by introducing DNA interstrand cross-links in vivo with 4,5',8- trimethylpsoralen and UV radiation. Electron microscopy of individual maxicircles resulting from a topoisomerase II decatenation of kinetoplast DNA networks revealed intact maxicircle θ structures. Analysis of maxicircle DNA linearized by restriction enzyme cleavage revealed branched replication intermediates derived from θ structures. Measurements of the linearized branched molecules in both parasites indicate that replication initiates in the variable region (a noncoding segment characterized by repetitive sequences) and proceeds unidirectionally, clockwise on the standard map.
UR - http://www.scopus.com/inward/record.url?scp=0028790840&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0028790840&partnerID=8YFLogxK
U2 - 10.1128/MCB.15.12.6794
DO - 10.1128/MCB.15.12.6794
M3 - Article
C2 - 8524245
AN - SCOPUS:0028790840
VL - 15
SP - 6794
EP - 6803
JO - Molecular and Cellular Biology
JF - Molecular and Cellular Biology
SN - 0270-7306
IS - 12
ER -