Organization of Ribosomal RNA Genes from a Loofah Witches' Broom Phytoplasma
| Autor: | Chi-Chang Tsai, Te-Lei Chung, Kuo-Chieh Ho |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Sequence analysis
Operon Molecular Sequence Data Gene Dosage Context (language use) Biology 5S ribosomal RNA Mycoplasma RNA Ribosomal 16S DNA Ribosomal Spacer Gene Order Genetics Amino Acid Sequence Cloning Molecular 3' Untranslated Regions Molecular Biology Gene Base Sequence RNA Ribosomal 5S Sequence Analysis DNA Cell Biology General Medicine Plants Ribosomal RNA biology.organism_classification Molecular biology RNA Bacterial RNA Ribosomal 23S Genes Bacterial RNA Ribosomal Phytoplasma RRNA Operon 5' Untranslated Regions |
| Zdroj: | DNA and Cell Biology. 20:115-122 |
| ISSN: | 1557-7430 1044-5498 |
| DOI: | 10.1089/104454901750070328 |
| Popis: | Using the technique of integrative mapping with three vectors carrying chromosomal rDNA sequences, one of two rRNA operons of loofah witches' broom (LfWB) phytoplasma was constructed. This is the first complete rRNA operon of a phytoplasma to be reported. The operon has a context of 5'-16S-23S-5S-3' with a tRNA(Ile) gene in the ITS and tRNA(Val) and tRNA(Asn) genes downstream from the 5S rRNA gene. Although the other operon has not been cloned, the DNA sequence of a PCR-amplified product shows that it has no tRNA(Ile) gene in the ITS region. The complete nucleotide sequences of 16S, 23S, and 5S rDNA are 1538, 2864, and 113 bp, respectively. Five -10-like sequences, but no -35 sequences, were found within a 494-bp leader region. There was a TG dinucleotide two nucleotides upstream from each -10-like sequence. The existence of a TG dinucleotide at this position has been reported to enhance the efficiency of a promoter without a -35 region. The regions immediately flanking the 5' and 3' ends of 16S and 23S rDNA can form long basepaired stems that contain sites for processing by RNase III. No obvious sequence for a rho-dependent or rho-independent termination site was found downstream from the tRNA(Asn) gene. The transcription may stop within a pyrimidine-rich region, as has been reported for several polypeptide-encoding genes and rRNA operons of archaeobacteria. The presence of the tRNA genes downstream from the 5S rRNA gene in the rRNA operon of LfWB phytoplasma further supports the hypothesis that phytoplasmas are phylogenetically closer to acholeplasmas than to mycoplasmas. The phylogenetic relatedness of LfWB phytoplasma to other phytoplasmas is discussed on the basis of the nucleotide sequence of rRNA genes and ITS. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|