RNA polymerase II of Drosophila: Relation of its 140,000 Mr subunit to the β subunit of Escherichia coli RNA polymerase

We have determined the nucleotide sequence of the gene coding for the 140,000 M r subunit of the DNA-dependent RNA polymerase II from Drosophila melanogaster. ‡ ‡ These sequence data have been submitted by the EMBL/Gen Bank Libraries under the accession number 4 00 162. This analysis revealed features that are typical for a household-function gene. The codon usage is relaxed and there is no apparent TATA box upstream from the transcription start site. A comparison of the deduced amino acid sequence with that of the Escherichia coli RNA polymerase β subunit shows a total of nine regions of homology. These regions are also conserved in chloroplast DNA of tobacco. This supports the notion that the two large subunits of the eukaryotic RNA polymerases are the structural and functional equivalents of E. coli β′ and β subunits.