Mitochondrial-like DNA sequences flanked by direct and inverted repeats in the nuclear genome of Toxoplasma gondii.
J Mol Biol
; 222(3): 525-36, 1991 Dec 05.
Article
em En
| MEDLINE
| ID: mdl-1660924
ABSTRACT
In the course of our genetic studies on Toxoplasma gondii, it was discovered that one cosmid hybridized to a repetitive element. The hybridization pattern observed for the enzyme BglII indicated that this cosmid hybridized to a large number of discrete, but related elements. Four BglII fragments were subcloned from the cosmid, and each was shown to hybridize with all the others, as well as to numerous dispersed sequences in genomic DNA. Three subclones were sequenced in their entirety, and shown to contain fragments of the genes for cytochrome oxidase subunit I and apocytochrome b, complete and functional copies of which have been found in only mitochondrial genomes. All the subcloned fragments were bounded at both ends by a 91 base-pair sequence, which contains a site for BglII. This 91 base-pair sequence could be found as either a direct or inverted repeat. It was determined that the BglII elements are arrayed downstream from a single copy nuclear gene. Comparison of genomic and cosmid DNAs confirmed that the cosmid faithfully reflects the nuclear genome. Although the mitochondrial genome of Toxoplasma has not been characterized, these nuclear mitochondrial-like sequences appear to be internally rearranged with respect to known, functional mitochondrial genomes, and with respect to each other. The finding of short repeated sequences flanking these elements may be a clue to the mechanism of their dissemination.
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Base de dados:
MEDLINE
Assunto principal:
Toxoplasma
/
DNA Mitocondrial
/
Sequências Repetitivas de Ácido Nucleico
/
Núcleo Celular
/
Genoma
Limite:
Animals
Idioma:
En
Revista:
J Mol Biol
Ano de publicação:
1991
Tipo de documento:
Article