Genes for the eight ribosomal proteins are clustered on the chloroplast genome of tobacco (Nicotiana tabacum): similarity to the S10 and spc operons of Escherichia coli.

Abstract

The nucleotide sequence of a tobacco (Nicotiana tabacum) chloroplast gene cluster that encodes eight proteins homologous to Escherichia coli ribosomal proteins L23, L2, S19, L22, S3, L16, L14, and S8 has been determined. RNA gel blot hybridization revealed that all eight coding regions are expressed in the chloroplasts. The arrangement of the eight genes resembles that found in the E. coli S10 and spc operons. Among the eight genes, the L2 and L16 genes contain 666- and 1020-base-pair introns, respectively. These intron boundary sequences are consistent with the conserved boundary sequences of the chloroplast group III introns [Shinozaki, K., Deno, H., Sugita, M., Kuramitsu, S. & Sugiura, M. (1986) Mol. Gen. Genet. 202, 1-5].