To extend elongation into the transcription unit, a kinase complex called P-TEFb is required. P-TEFb contains the CDK9 kinase, which is a member of the kinase family that controls the cell cycle. P-TEFb acts on the CTD to phosphorylate it further on serine 2 of the heptapeptide repeat.

TLS Online TPP Program

#Id: 2949

#Unit 3. Fundamental Processes

an ARS for autonomously replicating sequence, ARS elements are derived from origins of replication.

TLS Online TPP Program

#Id: 2950

#Unit 3. Fundamental Processes

An ARS element consists of an A-T-rich region that contains discrete sites in which mutations affect origin function.

TLS Online TPP Program

#Id: 2951

#Unit 3. Fundamental Processes

An ARS extends for -so bp and includes a consensus sequence (A} and additional elements (B1-B3).

TLS Online TPP Program

#Id: 2952

#Unit 3. Fundamental Processes

Mutations in three adjacent elements, numbered B 1 to B3, reduce origin function.

TLS Online TPP Program

#Id: 2953

#Unit 3. Fundamental Processes

By counting the number of sites to which ORC binds, we can estimate that there are about 400 origins of replication in the yeast genome.

TLS Online TPP Program

#Id: 2954

#Unit 3. Fundamental Processes

By counting the number of sites to which ORC binds, we can estimate that there are about 400 origins of replication in the yeast genome. This means that the average length of a replicon is -35,000 bp.