Multiple Forms of RNA Polymerase in Xenopus laevis: Their Relationship to RNA Synthesis in vivo and Their Fidelity of Transcription in vitro

Any mechanisms proposed for gene control during development must account for the fact that some unlinked genes are expressed coordinately. An obvious means to accomplish this would be to furnish these genes with identical nucleotide sequences in their promoter regions. A single species of RNA polymerase specific for this particular promoter sequence could then effect coordinate expression of the unlinked genes. The recent discovery in several eucaryotes of multiple forms of RNA polymerase (Roeder, 1969; Roeder and Rutter, 1969) with specific subcellular localizations (Roeder and Rutter, 1970a) has made such a scheme more plausible.