Changes in network topology during the replication of kinetoplast DNA

被引:51
作者
Chen, JH [1 ]
Englund, PT [1 ]
Cozzarelli, NR [1 ]
机构
[1] JOHNS HOPKINS UNIV,SCH MED,DEPT BIOL CHEM,BALTIMORE,MD 21205
关键词
Crithidia fasciculata; DNA topology; kinetoplast DNA; replication;
D O I
10.1002/j.1460-2075.1995.tb00325.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Kinetoplast DNA of Crithidia fasciculata is a network containing several thousand topologically interlocked DNA minicircles. In the prereplicative Form I network, each of the 5000 minicircles is intact and linked to an average of three neighbors (i.e. the minicircle valence is 3), Replication involves the release of minicircles from the interior of the network, the synthesis of nicked or gapped progeny minicircles and the attachment of the progeny to the network periphery, The ultimate result is a Form II network of 10 000 nicked or gapped minicircles. Our measurements of minicircle valence and density, and the network's surface area, revealed striking changes in network topology during replication, During the S phase, the peripheral newly replicated minicircles have a density twice that of minicircles in Form I networks, which suggests that the valence might be as high as 6, Most of the holes in the central region that occur from the removal of intact minicircles are repaired so that the central density and valence remain the same, as in prereplicative networks. When minicircle replication is complete at the end of the S phase, the isolated network has the surface area of a prereplicative network, despite having twice the number of minicircles. During the G(2) phase, the Form II network undergoes a remodeling in which the area doubles and the valence is reduced to 3, Finally, the interruptions in the minicircles are repaired and the double-sized network splits in two.
引用
收藏
页码:6339 / 6347
页数:9
相关论文
共 25 条
[11]   LOCALIZATION OF A TYPE-II DNA TOPOISOMERASE TO 2 SITES AT THE PERIPHERY OF THE KINETOPLAST DNA OF CRITHIDIA FASCICULATA [J].
MELENDY, T ;
SHELINE, C ;
RAY, DS .
CELL, 1988, 55 (06) :1083-1088
[12]   THE STRUCTURE OF REPLICATING KINETOPLAST DNA NETWORKS [J].
PEREZMORGA, D ;
ENGLUND, PT .
JOURNAL OF CELL BIOLOGY, 1993, 123 (05) :1069-1079
[13]   THE ATTACHMENT OF MINICIRCLES TO KINETOPLAST DNA NETWORKS DURING REPLICATION [J].
PEREZMORGA, DL ;
ENGLUND, PT .
CELL, 1993, 74 (04) :703-711
[14]   THE ABSENCE OF SUPERCOILING IN KINETOPLAST DNA MINICIRCLES [J].
RAUCH, CA ;
PEREZMORGA, D ;
COZZARELLI, NR ;
ENGLUND, PT .
EMBO JOURNAL, 1993, 12 (02) :403-411
[15]   KINETOPLAST DNA MINICIRCLES - HIGH-COPY-NUMBER MITOCHONDRIAL PLASMIDS [J].
RAY, DS .
PLASMID, 1987, 17 (03) :177-190
[16]   FORM AND STRUCTURE OF KINETOPLAST DNA OF CRITHIDIA [J].
RENGER, HC ;
WOLSTENHOLME, DR .
JOURNAL OF CELL BIOLOGY, 1972, 54 (02) :346-+
[17]   THE STRUCTURE AND REPLICATION OF KINETOPLAST DNA [J].
SHAPIRO, TA ;
ENGLUND, PT .
ANNUAL REVIEW OF MICROBIOLOGY, 1995, 49 :117-143
[18]   THE ASSEMBLY OF KINETOPLAST DNA [J].
SHLOMAI, J .
PARASITOLOGY TODAY, 1994, 10 (09) :341-346
[19]   PULSE-LABELING OF KINETOPLAST DNA - LOCALIZATION OF 2 SITES OF SYNTHESIS WITHIN NETWORKS AND KINETICS OF LABELING OF CLOSED MINICIRCLES [J].
SIMPSON, AM ;
SIMPSON, L .
JOURNAL OF PROTOZOOLOGY, 1976, 23 (04) :583-587
[20]   RNA EDITING AND THE EVOLUTION OF PARASITES [J].
SIMPSON, L ;
MASLOV, DA .
SCIENCE, 1994, 264 (5167) :1870-1871