Sequence analysis of the second largest subunit of tomato RNA polymerase II.

We have cloned and sequenced the cDNA encoding the open reading frame of the mRNA of the second largest subunit of RNA polymerase II, or RPB2, of tomato. The mRNA is transcribed from a single-copy gene in the tomato genome and the transcript size of the gene was measured as 4.2 kb by northern analysis. From the deduced amino acid sequence of 1191 residues, a protein of M r 135 000 with an isoelectric point of pH 7.9 was predicted. Alignment of the tomato RPB2 protein sequence with those of the homologous subunits in Arabidopsis, man, Drosophila and yeast showed considerable sequence identity.