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The Info List - Replicon (genetics)


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A replicon is a DNA
DNA
molecule or RNA
RNA
molecule, or a region of DNA
DNA
or RNA, that replicates from a single origin of replication.

Contents

1 Prokaryotes 2 Eukaryotes 3 See also 4 References

Prokaryotes[edit] For most prokaryotic chromosomes, the replicon is the entire chromosome. One notable exception found comes from archaea, where two Sulfolobus
Sulfolobus
species have been shown to contain three replicons. Examples of bacterial species that have been found to possess multiple replicons include: Rhodobacter sphaeroides (2), Vibrio cholerae,[1] and Burkholderia multivorans (3). These "secondary" (or tertiary) chromosomes are often described as a molecule that is a mixture between a true chromosome and a plasmid and are sometimes called "chromids". Various Azospirillum species possess 7 replicons, Azospirillum lipoferum, for instance, has 1 bacterial chromosome, 5 chromids, and 1 plasmid.[2] Plasmids and bacteriophages are usually replicated as single replicons, but large plasmids in Gram-negative bacteria have been shown to carry several replicons.[3] Eukaryotes[edit] For eukaryotic chromosomes, there are multiple replicons per chromosome. In the case of mitochondria the definition of replicons is somewhat confused, as they use unidirectional replication with two separate origins. See also[edit]

Origin of replication

References[edit]

^ Tagomori, K.; Iida, T.; Honda, T. (2002). "Comparison of genome structures of vibrios, bacteria possessing two chromosomes". Journal of Bacteriology. 184 (16): 4351–4358. doi:10.1128/JB.184.16.4351-4358.2002. PMC 135242 . PMID 12142404.  ^ Wisniewski-Dyé, F.; Borziak, K.; Khalsa-Moyers, G.; Alexandre, G.; Sukharnikov, L. O.; Wuichet, K.; Hurst, G. B.; McDonald, W. H.; Robertson, J. S.; Barbe, V.; Calteau, A.; Rouy, Z.; Mangenot, S.; Prigent-Combaret, C.; Normand, P.; Boyer, M.; Siguier, P.; Dessaux, Y.; Elmerich, C.; Condemine, G.; Krishnen, G.; Kennedy, I.; Paterson, A. H.; González, V.; Mavingui, P.; Zhulin, I. B. (2011). Richardson, Paul M, ed. " Azospirillum Genomes Reveal Transition of Bacteria from Aquatic to Terrestrial Environments". PLoS Genetics. 7 (12): e1002430. doi:10.1371/journal.pgen.1002430. PMC 3245306 . PMID 22216014.  ^ Thomas, Christopher M. (2000-05-01). Horizontal Gene Pool: Bacterial Plasmids and Gene Spread (1 ed.). CRC Press. ISBN 9057024624. 

v t e

DNA
DNA
replication (comparing Prokaryotic
Prokaryotic
to Eukaryotic)

Initiation

Prokaryotic (initiation)

Pre-replication complex

dnaC

Cdc6

Helicase

dnaA dnaB T7

Primase

dnaG

Eukaryotic (preparation in G1 phase)

Pre-replication complex

Origin recognition complex

ORC1 ORC2 ORC3 ORC4 ORC5 ORC6

Cdc6

Cdt1

Minichromosome maintenance

MCM2 MCM3 MCM4 MCM5 MCM6 MCM7

Licensing factor

Autonomously replicating sequence

Single-strand binding protein

SSBP2 SSBP3 SSBP4

RNase H

RNASEH1 RNASEH2A

Helicase: HFM1

Primase: PRIM1 PRIM2

Both

Origin of replication/Ori/Replicon

Replication fork

Lagging and leading strands

Okazaki fragments Primer

Replication

Prokaryotic (elongation)

DNA
DNA
polymerase III holoenzyme

dnaC dnaE dnaH dnaN dnaQ dnaT dnaX holA holB holC holD holE

Replisome DNA
DNA
ligase DNA
DNA
clamp Topoisomerase

DNA
DNA
gyrase

Prokaryotic
Prokaryotic
DNA
DNA
polymerase: DNA
DNA
polymerase I

Klenow fragment

Eukaryotic (synthesis in S phase)

Replication factor C

RFC1

Flap endonuclease

FEN1

Topoisomerase Replication protein A

RPA1

Eukaryotic DNA
DNA
polymerase: alpha

POLA1 POLA2 PRIM1 PRIM2

delta

POLD1 POLD2 POLD3 POLD4

epsilon

POLE POLE2 POLE3 POLE4

DNA
DNA
clamp

PCNA

Control of chromosome duplication

Both

Movement: Processivity DNA
DNA
ligase

Termination

Telomere: Telomerase

TERT TERC DKC1

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