Identification of a sequence responsible for periodic synthesis of yeast histone 2A mRNA.

Sequences required for the regulated expression of a yeast histone 2A (H2A) gene have been investigated by using fusions between this gene and the Escherichia coli lacZ gene. Fusions containing the entire spacer region in which divergent transcription of the H2A and H2B genes is initiated result in low-level constitutive synthesis of beta-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23) in yeast. Regulated expression (which is characterized by periodic synthesis during the S phase of the cell cycle) is restored when a 1.3-kilobase HindIII fragment containing a small region of the 3' end of the H2B gene is present in either orientation. The regulatory activity in this region appears to be coincident with a sequence that supports autonomous replication in yeast.