Capter 11: Replication and Recombination

Need more stuff for recombination

Replication fork

The area where DNA strands separate during DNA replication, allowing for the synthesis of new complementary strands. It is formed at the origin of replication by the action of helicase unwinding the double helix.

Replicon

The length of DNA that is replicated by a single fork/replication event

Chain elongation

Addition of nucleotides in the 5’-3’ direction attaching the “new” phosphate group to the existing 3’ OH

DNA pol I

An enzyme involved in DNA replication that synthesizes new DNA strands and has 5’-3’ exonuclease activity to remove RNA primers as well as 3’-5’ exonuclease activity for proofreading

Exonuclease

A type of enzyme that cleaves nucleotides one at a time from the end of a DNA or RNA molecule, involved in DNA replication and repair processes.

Bacterial DNA Pol II

Possesses 5’-3’ polymerization capacity and also 3’ - 5’ exonuclease activity. Involved in various aspects of DNA repair.

bacterial DNA Pol III

Most likely the main player in the 5’-3’ polymerization necessary for DNA replication. Also possesses 3’-5’ exonuclease activity for proofreading.

holoenzyme

A multifunctional enzyme complex that includes multiple subunits, typically made up of enzyme and coenzymes

DNA pol III Holoenzyme

Made up of at least 10 subunits. All of them are required for a fully functional enzyme

Eukaryotic replication origins

Sites where DNA replication begins in eukaryotic cells, typically characterized by specific sequences that are recognized by the replication machinery. Multiple ORIs exist on each chromosome, allowing for the efficient replication of DNA

Origin Replication Complex

A multi-protein complex that binds to replication origins in eukaryotic cells and is essential for the initiation of DNA replication. Made up by ORC1-6

pre-RC

After the ORC is formed, additional proteins, including Cdc6, Cdt1, and Mcm2-7 are recruited to form the pre-replication complex, which is essential for DNA replication.

Mcm2-7

A hexameric protein complex composed of Mcm2, Mcm3, Mcm4, Mcm5, Mcm6, and Mcm7 proteins, which have helicase activity essential for DNA replication.

Cdc6

A protein that is required for the recruitment of the Mcm2-7 complex to the pre-replication complex (pre-RC)

Cdt1

The essential “licensing factor” that helps initiate replication forks as a member of the pre-RC

Eukaryotic pol alpha

Makes RNA/DNA primers, initiation of DNA synthesis. Has low processivity which allows for polymerase switching after RNA primers are generated

Pol delta

Lagging strand synthesis, repair, recombination, and proofreading

Pol epsilon

Leading strand synthesis, repair, recombination, and proofreading

Pol gamma

mitochondrial DNA replication and repair

Okazaki fragment size

100-150 bp in eukaryotes

Holliday Junction

an intermediate structure formed during homologous recombination where two DNA molecules are interconnected.

Homologous recombination

a process by which genetic material is exchanged between similar or identical DNA molecules, leading to genetic diversity and repair.

___ DNA is necessary for HR

Single Stranded