201:. This makes use of the intact chromosome homologous to the broken one as a template to bring the two double-stranded pieces into correct alignment for rejoining. Early in this process, one strand of one piece is matched to a strand of the intact chromosome and that strand is used to form a D-loop at that point, displacing the intact chromosome's other strand. Various ligation and synthesis steps follow to effect the rejoining.
233:
A current model of meiotic recombination, initiated by a double-strand break or gap, followed by pairing with an homologous chromosome and strand invasion to initiate the recombinational repair process. Repair of the gap can lead to crossover (CO) or non-crossover (NCO) of the flanking regions. CO
125:
Replication of the mitochondrial DNA can occur in two different ways, both starting in the D-loop region. One way continues replication of the heavy strand through a substantial part (e.g. two-thirds) of the circular molecule, and then replication of the light strand begins. The more recently
265:
filaments that perform a search for intact homologous double-stranded DNA (dsDNA). Once the homologous sequence is found, the recombinases facilitate invasion of the ssDNA end into the homologous dsDNA to form a D-loop. After strand exchange,
238:(DHJ) model, illustrated on the right, above. NCO recombinants are thought to occur primarily by the Synthesis Dependent Strand Annealing (SDSA) model, illustrated on the left, above. Most recombination events appear to be the SDSA type.
117:
of the heavy strand that has been arrested shortly after initiation and is often maintained for some period in that state. The D-loop occurs in the main non-coding area of the mitochondrial DNA molecule, a segment called the
104:
discovered in 1971 that the circular mitochondrial DNA from growing cells included a short segment of three strands which they called a displacement loop. They found the third strand was a replicated segment of the
246:, repair of double-strand damages, particularly double-strand breaks, occurs by the recombination process outlined in the accompanying diagram. As shown in the diagram, a D-loop plays a central role in meiotic
679:
He, J.; Mao, C. -C.; Reyes, A.; Sembongi, H.; Di Re, M.; Granycome, C.; Clippingdale, A. B.; Fearnley, I. M.; Harbour, M.; Robinson, A. J.; Reichelt, S.; Spelbrink, J. N.; Walker, J. E.; Holt, I. J. (2007).
129:
Certain bases within the D-loop region are conserved, but large parts are highly variable and the region has proven to be useful for the study of the evolutionary history of vertebrates. The region contains
142:
from the two strands of mitochondrial DNA immediately adjacent to the D-loop structure that is associated with initiation of DNA replication. D-loop sequences are also of interest in the study of cancers.
230:
942:"Homologous genetic recombination as an intrinsic dynamic property of a DNA structure induced by RecA/Rad51-family proteins: A possible advantage of DNA over RNA as genomic material"
636:
Akouchekian, M.; Houshmand, M.; Hemati, S.; Ansaripour, M.; Shafa, M. (2009). "High Rate of
Mutation in Mitochondrial DNA Displacement Loop Region in Human Colorectal Cancer".
170:-like structure termed a T-loop (Telomere-loop). This is a loop of both strands of the chromosome which are joined to an earlier point in the double-stranded DNA by the
74:. A diagram in the paper introducing the term illustrated the D-loop with a shape resembling a capital "D", where the displaced strand formed the loop of the "D".
526:
Larizza, A.; Pesole, G.; Reyes, A.; SbisĂ , E.; Saccone, C. (2002). "Lineage specificity of the evolutionary dynamics of the mtDNA D-loop region in rodents".
126:
reported mode starts at a different origin within the D-loop region and uses coupled-strand replication with simultaneous synthesis of both strands.
54:
structure where the two strands of a double-stranded DNA molecule are separated for a stretch and held apart by a third strand of DNA. An
146:
The function of the D-loop is not yet clear, but recent research suggests that it participates in the organization of the mitochondrial
70:
with it, thus displacing the other complementary main strand in the region. Within that region the structure is thus a form of
113:
to the light strand (or L-strand). Since then, it has been shown that the third strand is the initial segment generated by a
367:"Elongation of displacement-loop strands in human and mouse mitochondrial DNA is arrested near specific template sequences"
63:
682:"The AAA+ protein ATAD3 has displacement loop binding properties and is involved in mitochondrial nucleoid organization"
270:
intermediates are processed by either of two distinct pathways (see diagram) to form the final recombinant chromosomes.
924:
171:
190:
When a double-stranded DNA molecule has suffered a break in both strands, one repair mechanism available in
58:
is similar to a D-loop, but in that case the third strand is RNA rather than DNA. The third strand has a
770:
Griffith, J. D.; Comeau, L.; Rosenfield, S.; Stansel, R. M.; Bianchi, A.; Moss, H.; De Lange, T. (1999).
182:. The T-loop, which is completed by the D-loop splice, protects the end of the chromosome from damage.
267:
247:
135:
1001:"Connecting by breaking and repairing: mechanisms of DNA strand exchange in meiotic recombination"
940:
Shibata, T.; Nishinaka, T.; Mikawa, T.; Aihara, H.; Kurumizaka, H.; Yokoyama, S.; Ito, Y. (2001).
198:
953:
590:
535:
443:
429:"Discovery of a major D-loop replication origin reveals two modes of human mtDNA synthesis"
428:
378:
319:
284:
119:
8:
308:"A novel closed-circular mitochondrial DNA with properties of a replicating intermediate"
167:
71:
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39:
665:
579:"Priming of human mitochondrial DNA replication occurs at the light-strand promoter"
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Proceedings of the
National Academy of Sciences of the United States of America
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Proceedings of the
National Academy of Sciences of the United States of America
371:
Proceedings of the
National Academy of Sciences of the United States of America
312:
Proceedings of the
National Academy of Sciences of the United States of America
547:
487:"Coupled leading- and lagging-strand synthesis of mammalian mitochondrial DNA"
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invading the strand pair to form a D-loop. The joint is stabilized by the
831:
746:
258:
255:
208:
is central to the homologous search and formation of the D-loop. In the
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194:
163:
78:
59:
209:
175:
67:
635:
904:
159:
147:
82:
243:
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101:
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D-loops occur in a number of particular situations, including in
769:
55:
251:
205:
32:
939:
261:
bind the 3’ single-strand DNA (ssDNA) tails to form helical
218:
179:
109:(or H-strand) of the molecule, which it displaced, and was
305:
139:
51:
24:
20:
525:
810:
306:
Kasamatsu, H.; Robberson, D. L.; Vinograd, J. (1971).
485:Holt, I. J.; Lorimer, H. E.; Jacobs, H. T. (2000).
365:Doda, J. N.; Wright, C. T.; Clayton, D. A. (1981).
912:
906:
678:
484:
364:
217:, a similar function is performed by the protein
1045:
772:"Mammalian telomeres end in a large duplex loop"
426:
234:recombination is thought to occur by the Double
905:Hartl, Daniel L.; Jones, Elizabeth W. (2005).
250:repair of such damages. During this process,
992:
804:
763:
576:
998:
933:
857:
301:
299:
813:"Solving the Telomere Replication Problem"
519:
1024:
975:
965:
881:
840:
830:
811:Maestroni L, Matmati S, Coulon S (2017).
787:
754:
722:
705:
612:
602:
502:
427:Fish, J.; Raule, N.; Attardi, G. (2004).
400:
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341:
331:
570:
296:
228:
224:
915:Genetics: Analysis of Genes and Genomes
863:
478:
358:
1046:
728:
422:
420:
672:
577:Chang, D. D.; Clayton, D. A. (1985).
27:that forms the end of the D arm of a
85:, and as a semi-stable structure in
919:. Jones & Bartlett Publishers.
417:
13:
638:Diseases of the Colon & Rectum
95:
14:
1070:
185:
898:
199:homologous recombination repair
153:
66:to one of the main strands and
629:
528:Journal of Molecular Evolution
1:
883:10.1016/s0092-8674(00)80750-3
789:10.1016/S0092-8674(00)80760-6
504:10.1016/s0092-8674(00)80688-1
290:
158:In 1999 it was reported that
999:Sansam CL, Pezza RJ (2015).
866:"Telomeres do D-loop-T-loop"
650:10.1007/DCR.0b013e31819acb99
7:
735:The Journal of Cell Biology
686:The Journal of Cell Biology
273:
23:structure. For the loop of
10:
1075:
18:
548:10.1007/s00239-001-0063-4
268:homologous recombination
864:Greider, C. W. (1999).
456:10.1126/science.1102077
392:10.1073/pnas.78.10.6116
204:In humans, the protein
162:, which cap the end of
967:10.1073/pnas.111005198
333:10.1073/pnas.68.9.2252
239:
19:This article is about
731:"Thrown for a D-loop"
698:10.1083/jcb.200609158
604:10.1073/pnas.82.2.351
232:
225:Meiotic recombination
832:10.3390/genes8020055
747:10.1083/jcb.1762iti3
285:mtDNA control region
958:2001PNAS...98.8425S
729:Leslie, M. (2007).
595:1985PNAS...82..351C
540:2002JMolE..54..145L
448:2004Sci...306.2098F
442:(5704): 2098–2101.
383:1981PNAS...78.6116D
324:1971PNAS...68.2252K
72:triple-stranded DNA
1017:10.1111/febs.13317
280:D-loop replication
240:
122:or D-loop region.
62:sequence which is
952:(15): 8425–8432.
377:(10): 6116–6120.
236:Holliday Junction
166:, terminate in a
44:displacement loop
40:molecular biology
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318:(9): 2252–2257.
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214:Escherichia coli
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248:recombinational
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111:hydrogen bonded
100:Researchers at
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96:In mitochondria
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926:978-0763715113
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589:(2): 351–355.
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120:control region
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31:molecule, see
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263:nucleoprotein
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186:In DNA repair
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172:3' strand end
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136:transcription
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93:
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87:mitochondrial
84:
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73:
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64:complementary
61:
57:
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45:
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34:
30:
26:
22:
16:DNA structure
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259:recombinases
241:
212:
203:
189:
157:
154:In telomeres
145:
128:
124:
107:heavy strand
99:
90:circular DNA
76:
47:
43:
37:
29:transfer RNA
741:(2): 129a.
164:chromosomes
115:replication
92:molecules.
1048:Categories
908:"page 251"
825:(2): E55.
291:References
195:eukaryotic
79:DNA repair
1059:Telomeres
210:bacterium
197:cells is
176:shelterin
160:telomeres
132:promoters
83:telomeres
1035:25953379
986:11459985
892:10338204
851:28146113
798:10338214
716:17210950
666:28775491
658:19333057
564:40529707
556:11821908
513:10721989
472:36033690
464:15604407
274:See also
178:protein
148:nucleoid
134:for the
1026:4573575
954:Bibcode
842:5333044
756:2063944
707:2063933
623:2982153
591:Bibcode
536:Bibcode
444:Bibcode
436:Science
411:6273850
379:Bibcode
352:5289384
320:Bibcode
244:meiosis
242:During
192:diploid
102:Caltech
1033:
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1005:FEBS J
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402:348988
399:
350:
343:389395
340:
168:lariat
56:R-loop
48:D-loop
977:37453
818:Genes
662:S2CID
560:S2CID
468:S2CID
432:(PDF)
252:Rad51
206:RAD51
81:, in
68:pairs
50:is a
33:D arm
1031:PMID
982:PMID
921:ISBN
888:PMID
870:Cell
847:PMID
794:PMID
776:Cell
712:PMID
654:PMID
619:PMID
552:PMID
509:PMID
491:Cell
460:PMID
407:PMID
348:PMID
256:Dmc1
254:and
219:RecA
180:POT1
60:base
42:, a
1054:DNA
1021:PMC
1013:doi
1009:282
972:PMC
962:doi
878:doi
837:PMC
827:doi
784:doi
751:PMC
743:doi
739:176
702:PMC
694:doi
690:176
646:doi
609:PMC
599:doi
544:doi
499:doi
495:100
452:doi
440:306
397:PMC
387:doi
338:PMC
328:doi
140:RNA
138:of
52:DNA
46:or
38:In
25:RNA
21:DNA
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