A pseudogene cluster in the leader region of the Euglena chloroplast 16S-23S rRNA genes.
AUTOR(ES)
Miyata, T
RESUMO
The nucleotide sequence of a region (leader region) preceding the 5'-end of 16S-23S rRNA gene region of Euglena gracilis chloroplast DNA was compared with the homologous sequences that code for the 16S-23S rRNA operons of Euglena and E. coli. The leader region shows close homology in sequence to the 16S-23S rRNA gene region of Euglena (Orozco et al. (1980) J. Biol.Chem. 255, 10997-11003) as well as to the rrnD operon of E. coli, suggesting that it was derived from the 16S-23S rRNA gene region by gene duplication. It was shown that the leader region had accumulated nucleotide substitutions at an extremely rapid rate in its entirety, similar to the rate of tRNAIle pseudogene identified in the leader region. In addition, the leader region shows an unique base content which is quite distinct from those of 16S-23S rRNA gene regions of Euglena and E. coli, but again is similar to that of the tRNAIle pseudogene. The above two results strongly suggest that the leader region contains a pseudogene cluster which was derived from a gene cluster coding for the functional 16S-23S rRNA operon possibly by imperfect duplication during evolution of Euglena chloroplast DNA.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=320565Documentos Relacionados
- Acholeplasma laidlawii has tRNA genes in the 16S-23S spacer of the rRNA operon.
- Novel tRNA gene organization in the 16S-23S intergenic spacer of the Streptococcus pneumoniae rRNA gene cluster.
- Nucleotide sequence of the 16S - 23S spacer region in an rRNA gene cluster from tobacco chloroplast DNA.
- Phytoplasma-specific PCR primers based on sequences of the 16S-23S rRNA spacer region.
- Differentiation of Two Biovars of Ureaplasma urealyticum Based on the 16S-23S rRNA Intergenic Spacer Region
