Autonomously Replicating Sequence

An autonomously replicating sequence (ARS) contains the origin of replication in the yeast genome. It contains four regions (A, B1, B2, and B3), named in order of their effect on plasmid stability; when these regions are mutated, replication does not initiate.

Element A is highly conserved, consisting of the consensus sequence:

5'- T/A T T T A Y R T T T T/A -3'

(where Y is either pyrimidine and R is either purine). When this element is mutated, the ARS loses all activity.

As seen above the ARS are considerably A-T rich which makes it easy for replicative proteins to disrupt the H-bonding in that area. ORC protein complex (Origin Recognition Complex) is bound at the ARS throughout the cell cycle, allowing replicative proteins access to the ARS.

Mutational analysis for the yeast ARS elements have shown that any mutation in the B1, B2 and B3 regions result in a reduction of function of the ARS element. A mutation in the A region results in a complete loss of function.

DNA replication (Prokaryotic, Eukaryotic) Separation and initiation Prokaryotic (initiation) Pre-replication complex Cdc6 Helicase dnaA dnaB T7 Primase dnaG Eukaryotic (preparation in G1 phase) Pre-replication complex: Origin recognition complex ORC1 ORC2 ORC3 ORC4 ORC5 ORC6 Minichromosome maintenance MCM2 MCM3 MCM4 MCM5 MCM6 MCM7 CDC6 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 fragment Primer Replication Prokaryotic (elongation) DNA polymerase III holoenzyme dnaC dnaE dnaH dnaN dnaQ dnaT dnaX holA holB holC holD holE Replisome DNA ligase DNA clamp Topoisomerase DNA gyrase Prokaryotic DNA polymerase: DNA polymerase I Klenow fragment Eukaryotic (synthesis in S phase) Replication factor C RFC1 Flap endonuclease FEN1 Topoisomerase Replication protein A RPA1 Eukaryotic DNA polymerase: delta POLD1 POLD2 POLD3 POLD4 DNA clamp PCNA Both Movement: Processivity DNA ligase Termination Telomere: Telomerase TERT TERC DKC1 See also: DNA replication and repair-deficiency disorder B bsyn: dna (repl, cycl, reco, repr) · tscr (fact, tcrg, nucl, rnat, rept, ptts) · tltn (risu, pttl, nexn) · dnab, rnab/runp · stru (domn, 1°, 2°, 3°, 4°)