In E. coli., DNA polymerase I (coded by polA) is involved in the repair of damaged DNA and, in a subsidiary role, in semiconservative replication.

#Id: 406

#Unit 2. Cellular Organization

In yeast, centromeric nucleosomes consist of Cse4, H4, and a nonhistone protein Scm3, in place of H2A-H2B dimers.

#Id: 407

#Unit 2. Cellular Organization

In Drosophila, the centromeric chromatin appears to consist of “hemisomes” containing one copy each of CenH3, H4, H2A, and H2B.

#Id: 408

#Unit 2. Cellular Organization

Histone H3.1 is replicative histone.

#Id: 409

#Unit 2. Cellular Organization

H3.3 is expressed throughout the cell cycle, in contrast to most histones that are expressed during S phase during replication.

#Id: 410

#Unit 2. Cellular Organization

H3.3 is available for assembly at any time in the cell cycle, and is incorporated at sites of active transcription, where nucleosomes become disrupted.

#Id: 411

#Unit 2. Cellular Organization

H3.3 is often referred to as a “replacement” histone.