scholarly journals Sea urchin egg mitochondrial DNA contains a short displacement loop (D-loop) in the replication origin region

1989 ◽  
Vol 17 (22) ◽  
pp. 8949-8965 ◽  
Author(s):  
Howard T. Jacobs ◽  
Elaine R. Herbert ◽  
James Rankine
Keyword(s):  
Mitochondrial Dna ◽  
Sea Urchin ◽  
Replication Origin ◽  
Sea Urchin Egg ◽  
D Loop ◽  
Origin Region

scholarly journals MITOCHONDRIAL DNA REPLICATION IN SEA URCHIN OOCYTES

1974 ◽  
Vol 63 (1) ◽  
pp. 146-159 ◽  
Author(s):  
Lloyd Matsumoto ◽  
Harumi Kasamatsu ◽  
Lajos Pikó ◽  
Jerome Vinograd
Keyword(s):  
Mitochondrial Dna ◽  
Ethidium Bromide ◽  
Sea Urchin ◽  
Gradient Centrifugation ◽  
Loop Model ◽  
Cscl Density Gradient ◽  
D Loop ◽  
A Cell ◽  
Mtdna Replication ◽  
Circular Template

Mitochondrial DNA (mtDNA) replicative intermediates from Strongylocentrotus purpuratus oocytes were isolated by ethidium bromide-CsCl density gradient centrifugation and examined by electron microscopy after formamide spreading. In some experiments, the mtDNA was radioactively labeled by exposing isolated oocytes to [3H]thymidine. Oocyte mtDNA replication appears to follow the displacement loop model outlined in mouse L cells. There are differences in detail. The frequency of D-loop DNA is much lower in oocytes, suggesting that the relative holding time at the D-loop stage is shorter. Duplex synthesis on the displaced strand occurs early and with multiple initiations. The frequency of totally duplex replicative forms, or Cairns' forms, is the highest reported for mtDNA. The differences may be related to the fact that oocyte mtDNA replication occurs in the absence of cell division and need not be coordinated with a cell cycle. Molecules with expanded D loops banded in the intermediate region between the lower and upper bands in an ethidium bromide-CsCl gradient, supporting the notion that displacement replication proceeds on a closed circular template which is subject to nicking-closing cycles. In mature sea urchin eggs, replicative forms are absent and virtually all the mtDNA is stored as clean circular duplexes. Some novel structural variants of superhelical circular DNA (molecules with denaturation loops and double branch-migrated replicative forms) are reported.

scholarly journals Properties of some monkey DNA sequences obtained by a procedure that enriches for DNA replication origins.

1985 ◽  
Vol 5 (7) ◽  
pp. 1621-1629 ◽  
Author(s):  
M Zannis-Hadjopoulos ◽  
G Kaufmann ◽  
S S Wang ◽  
R L Lechner ◽  
E Karawya ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Dna Sequences ◽  
Replication Origin ◽  
Repetitive Sequences ◽  
S Phase ◽  
Alpha Satellite ◽  
Highly Dispersed ◽  
D Loop ◽  
Bona Fide ◽  
Dna Replication Origins

Twelve clones of monkey DNA obtained by a procedure that enriches 10(3)- to 10(4)-fold for nascent sequences activated early in S phase (G. Kaufmann, M. Zannis-Hadjopoulos, and R. G. Martin, Mol. Cell. Biol. 5:721-727, 1985) have been examined. Only 2 of the 12 ors sequences (origin-enriched sequences) are unique (ors1 and ors8). Three contain the highly reiterated Alu family (ors3, ors9, and ors11). One contains the highly reiterated alpha-satellite family (ors12), but none contain the Kpn family. Those remaining contain middle repetitive sequences. Two examples of the same middle repetitive sequence were found (ors2 and ors6). Three of the middle repetitive sequences (the ors2-ors6 pair, ors5, and ors10) are moderately dispersed; one (ors4) is highly dispersed. The last, ors7, has been mapped to the bona fide replication origin of the D loop of mitochondrial DNA. Of the nine ors sequences tested, half possess snapback (intrachain reannealing) properties.

Properties of some monkey DNA sequences obtained by a procedure that enriches for DNA replication origins

1985 ◽  
Vol 5 (7) ◽  
pp. 1621-1629
Author(s):  
M Zannis-Hadjopoulos ◽  
G Kaufmann ◽  
S S Wang ◽  
R L Lechner ◽  
E Karawya ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Dna Sequences ◽  
Replication Origin ◽  
Repetitive Sequences ◽  
S Phase ◽  
Alpha Satellite ◽  
Highly Dispersed ◽  
D Loop ◽  
Bona Fide ◽  
Dna Replication Origins

Twelve clones of monkey DNA obtained by a procedure that enriches 10(3)- to 10(4)-fold for nascent sequences activated early in S phase (G. Kaufmann, M. Zannis-Hadjopoulos, and R. G. Martin, Mol. Cell. Biol. 5:721-727, 1985) have been examined. Only 2 of the 12 ors sequences (origin-enriched sequences) are unique (ors1 and ors8). Three contain the highly reiterated Alu family (ors3, ors9, and ors11). One contains the highly reiterated alpha-satellite family (ors12), but none contain the Kpn family. Those remaining contain middle repetitive sequences. Two examples of the same middle repetitive sequence were found (ors2 and ors6). Three of the middle repetitive sequences (the ors2-ors6 pair, ors5, and ors10) are moderately dispersed; one (ors4) is highly dispersed. The last, ors7, has been mapped to the bona fide replication origin of the D loop of mitochondrial DNA. Of the nine ors sequences tested, half possess snapback (intrachain reannealing) properties.

Sign in / Sign up

Export Citation Format

Share Document