Unusual organization of the rRNA genes in Rickettsia prowazekii

Andersson, Siv G. E.; Zomorodipour, Alireza; Winkler, Herbert H.; Kurland, C. G.

doi:10.1128/jb.177.14.4171-4175.1995

Cited by 59 publications

(38 citation statements)

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“…Alternative rRNA gene arrangements are characterized by very low copy numbers of the rRNA genes with loss of the classical operon structure (Pang & Winkler, 1993 ;Andersson et al, 1995). These atypical structures are hypothesized to have arisen from a progenitor with the classical multiple operon structure by mutation and then differential deletion of individual 16S, 23S or 5S rRNA genes (Andersson et al, 1995 ;Kurland & Andersson, 2000). Consistent with this hypothesis, atypical rRNA gene arrangements are conserved among closely related bacterial species.…”

supporting

confidence: 56%

“…Overall, the organization of the Anaplasma rRNA genes, with the loss of the typical operon structure and the presence of a single 16S gene that is separated from the linked 23S-5S genes, is similar to that reported for the genus Rickettsia (Andersson et al, 1995(Andersson et al, , 1998(Andersson et al, , 1999. The distance separating the 16S and the 23S-5S genes in A. marginale has not been determined, but it is at least 100 kb.…”

Section: F R Rurangirwa and Othersmentioning

confidence: 51%

“…This loss of the normal 16S-23S spacer region sequences containing tRNA genes also reflects the pattern seen with Rickettsia spp. (Andersson et al, 1995(Andersson et al, , 1998(Andersson et al, , 1999. In contrast, in A. marginale, the fmt gene encoding methionyl-tRNA Met f formyltransferase was not identified immediately upstream of the 23S rRNA gene as occurs in 13 species of Rickettsia (Andersson et al, 1999).…”

Section: F R Rurangirwa and Othersmentioning

confidence: 87%

“…Deviations from the typical 16S-23S-5S operon structure are rare, with the exception of obligate intracellular bacteria with small ( 1n5 Mb) genomes. Alternative rRNA gene arrangements are characterized by very low copy numbers of the rRNA genes with loss of the classical operon structure (Pang & Winkler, 1993 ;Andersson et al, 1995). These atypical structures are hypothesized to have arisen from a progenitor with the classical multiple operon structure by mutation and then differential deletion of individual 16S, 23S or 5S rRNA genes (Andersson et al, 1995 ;Kurland & Andersson, 2000).…”

mentioning

confidence: 99%

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Conservation of the unique rickettsial rRNA gene arrangement in Anaplasma.

Rurangirwa¹,

Brayton²,

McGuire³

et al. 2002

International Journal of Systematic and Evolutionary Microbiology

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The organization of the rRNA genes of Anaplasma marginale, the type species of the genus Anaplasma, was identified to determine if the atypical rRNA gene arrangement identified in rickettsiae preceded divergence of the order Rickettsiales into the families Anaplasmataceae and Rickettsiaceae. The rRNA genes are encoded by two unlinked units, each present in a single copy per A. marginale genome. The 16S rRNA gene is separated from the linked 23S and 5S rRNA genes by a minimum of 100 kb. Similar to species belonging to the genus Rickettsia, the typical bacterial 16S-23S spacer region containing tRNA genes has been lost in A. marginale. In contrast, the fmt gene located upstream of the 23S rRNA gene in most Rickettsia spp. is not maintained in A. marginale, consistent with the fmt arrangement being a relatively late event in the evolution of rickettsial species.

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supporting

confidence: 56%

Section: F R Rurangirwa and Othersmentioning

confidence: 51%

Section: F R Rurangirwa and Othersmentioning

confidence: 87%

mentioning

confidence: 99%

See 2 more Smart Citations

Conservation of the unique rickettsial rRNA gene arrangement in Anaplasma.

Rurangirwa¹,

Brayton²,

McGuire³

et al. 2002

International Journal of Systematic and Evolutionary Microbiology

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“…Neighbour-joining and maximum-parsimony methods gave identical sequences. Such a mechanism will account for the presence in R. prowazekii of one, unlinked copy of rrs and rrl, both of which are surrounded by new¯anking sequences 36 . Likewise, R. prowazekii has one tuf gene and one fus gene in atypical clusters that seem to have been created by intrachromosomal recombination between the two tuf genes that are normally found in Gram-negative bacteria 37 .…”

Section: Reductive Evolutionmentioning

confidence: 99%

The genome sequence of Rickettsia prowazekii and the origin of mitochondria

Andersson

Zomorodipour

Andersson

et al. 1998

Nature

1,527

1,093

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We describe here the complete genome sequence (1,111,523 base pairs) of the obligate intracellular parasite Rickettsia prowazekii, the causative agent of epidemic typhus. This genome contains 834 protein-coding genes. The functional pro®les of these genes show similarities to those of mitochondrial genes: no genes required for anaerobic glycolysis are found in either R. prowazekii or mitochondrial genomes, but a complete set of genes encoding components of the tricarboxylic acid cycle and the respiratory-chain complex is found in R. prowazekii. In effect, ATP production in Rickettsia is the same as that in mitochondria. Many genes involved in the biosynthesis and regulation of biosynthesis of amino acids and nucleosides in free-living bacteria are absent from R. prowazekii and mitochondria. Such genes seem to have been replaced by homologues in the nuclear (host) genome. The R. prowazekii genome contains the highest proportion of non-coding DNA (24%) detected so far in a microbial genome. Such non-coding sequences may be degraded remnants of`neutralized' genes that await elimination from the genome. Phylogenetic analyses indicate that R. prowazekii is more closely related to mitochondria than is any other microbe studied so far.The Rickettsia are a-proteobacteria that multiply in eukaryotic cells only. R. prowazekii is the agent of epidemic, louse-borne typhus in humans. Three features of this endocellular parasite deserve our attention. First, R. prowazekii is estimated to have infected 20±30 million humans in the wake of the First World War and killed another few million following the Second World War (ref. 1). Because it is the descendent of free-living organisms 2±4 , its genome provides insight into adaptations to the obligate intracellular lifestyle, with probable practical value. Second, phylogenetic analyses based on sequences of ribosomal RNA and heat-shock proteins indicate that mitochondria may be derived from the aproteobacteria 5,6 . Indeed, the closest extant relatives of the ancestor to mitochondria seem to be the Rickettsia 7±10 . That modern Rickettsia favour an intracellular lifestyle identi®es these bacteria as the sort of organism that might have initiated the endosymbiotic scenario leading to modern mitochondria 11 . Finally, the genome of R. prowazekii is a small one, containing only 1,111,523 base pairs (bp). Its phylogenetic placement and many other characteristics identify it as a descendant of bacteria with substantially larger genomes 2±4 . Thus Rickettsia, like mitochondria, are good examples of highly derived genomes, the products of several types of reductive evolution.The genome sequence of R. prowazekii indicates that these three features may be related. For example, prokaryotic genomes evolving within a cell dominated by a much larger, eukaryote genome and constrained by bottle-necked population dynamics will tend to lose genetic information 12,13 . Predictable sets of expendable genes will tend to disappear from the prokaryotic genome when they are made redundant by the activit...

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Identification of Microorganisms

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2019

Pharmaceutical Microbiological Quality Assurance and Control

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Unusual organization of the rRNA genes in Rickettsia prowazekii

Cited by 59 publications

References 0 publications

Conservation of the unique rickettsial rRNA gene arrangement in Anaplasma.

Conservation of the unique rickettsial rRNA gene arrangement in Anaplasma.

The genome sequence of Rickettsia prowazekii and the origin of mitochondria

Identification of Microorganisms

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