Clustering of RNA polymerase B molecules in the 5′ moiety of the adult β-globin gene of hen erythrocytes

Abstract

Nuclei were prepared from mature and immature hen erythro-cytes and incubated for RNA synthesis in the absence or in the presence of Sarkosyl. The in vitro labelled synthesized RNA was hybridized to specific 5′ and 3′ fragments of the chicken adult β-globin gene to investigate the possible presence of RNA polymerase molecules bound to this gene in the form of transcriptional complexes. Surprisingly, such RNA polymerase B molecules were found located preferentially in the 5′ end moiety of the β-globin genes of mature erythrocytes, although they are apparently evenly distributed along the β-globin genes of immature polychromatic erythrocytes. The significance of these observations with respect to (1) preferential DNaseI sensitivity of “genes which have been transcribed” and (2) control of transcription in eukaryotic cells is discussed.