- Pre-replication complex
A pre-replication complex (pre-RC) is a
protein complexthat forms at the origin of replicationduring the initiation step of DNA replication. The proteins involved in the pre-RC are essential for DNA replication.
The Prokaryotic Pre-RC
prokaryotes, the pre-RC is made up of the following factors :
helicasesuch as dnaA, which unwinds the DNAahead of the replication fork.
primasesuch as dnaG, which generates an RNAprimer to be used in DNA replication.
DNA holoenzyme, which is actually a complex of enzymes that performs the actual replication.
The Eukaryotic Pre-RC
eukaryotes, the pre-RC is made up of the following factors:
* A six-subunit complex called
Origin Recognition Complex(ORC) which binds to the origin.
* Two regulatory proteins called
Cdc6and Cdt1which are recruited by ORC.
* The MCMs (Minichromosome Maintenance proteins), the helicase complex.
These proteins assemble on cellular origins in
G1 phaseof the cell cycle. Once these proteins are assembled, the MCMs are phosphorylatedand DNA replicationbegins.
Eukaryotic DNA replication initiation summary [http://www.pubmedcentral.nih.gov/picrender.fcgi?tool=pmcentrez&blobtype=pdf&artid=138988]
Wikimedia Foundation. 2010.
Look at other dictionaries:
Pre-replication complex — … Википедия
Complex RISC — Le complexe RISC (en anglais RNA induced silencing complex) est un complexe multi protéique essentiel, qui joue un rôle central dans le phénomène d ARN interférence. Il permet, par le guidage de petits ARN non codant (endogènes ou étrangers), de… … Wikipédia en Français
Origin of replication — The origin of replication (also called the replication origin) is a particular sequence in a genome at which replication is initiated. This can either be DNA replication in living organisms such as prokaryotes and eukaryotes, or RNA… … Wikipedia
DNA replication factor CDT1 — Chromatin licensing and DNA replication factor 1 Identifiers Symbols CDT1; DUP; RIS2 External IDs … Wikipedia
Origin recognition complex — Potential role of Cdc6 at the initiation of DNA replication. ORC or Origin Recognition Complex is a multi subunit DNA binding complex (6 subunits) that binds in all eukaryotes in an ATP dependent manner to origins … Wikipedia
DNA replication — DNA replication. The double helix is unwound and each strand acts as a template for the next strand. Bases are matched to synthesize the new partner strands. DNA replication is a biological process that occurs in all living organisms and copies… … Wikipedia
Eukaryotic DNA replication — Although the mechanisms of DNA synthesis in eukaryotes and prokaryotes are similar, DNA replication in eukaryotes is much more complicated. Though DNA synthesis in prokaryotes such as E. coli is regulated, DNA replication is initiated before the… … Wikipedia
Self-replication — is any process by which a thing might make a copy of itself. Biological cells, given suitable environments, reproduce by cell division. During cell division, DNA is replicated and can be transmitted to offspring during reproduction. Biological… … Wikipedia
Control of chromosome duplication — A key feature of the DNA replication mechanism in eukaryotes is that it is designed to replicate relatively large genomes rapidly and with high fidelity. Replication is initiated at multiple origins of replication on multiple chromosomes… … Wikipedia
ORC1 — Origin recognition complex, subunit 1 Identifiers Symbols ORC1; HSORC1; ORC1L; PARC1 External IDs … Wikipedia