ABSTRACT
Chromatin can act as a template for in vitro ribonucleic acid (RNA) transcription by bacterial RNA polymerase suggested a cell-free approach to studying selective gene expression. Endogenous RNA is tightly bound to chromatin and can only be removed by drastic procedures such as RNAse digestion or total dissociation of the chromatin in cesium chloride. This chapter summarizes that during reconstitution, provided adequate controls are done, there is a specific interaction of deoxyribonucleic acid (DNA) and protein sequences which promotes selective expression of the globin gene during transcription. While nonhistone proteins (NHP) purified on CsClrurea prior to reconstitution is free of endogenous globin messenger RNA (mRNA) sequences as judged by hybridization to complementary DNA (cDNA), it is difficult to detect small amounts of other RNAs which might still be present in this fraction. The possibility that small amounts of RNA associated with NHP may have a role in gene regulation cannot be excluded at this stage.
