INVESTIGADORES
MORETTA Rosalia Ester
congresos y reuniones científicas
Título:
Tandem repeats a new tools for Anaplasma marginale epidemiological studies
Autor/es:
RUYBAL P.; MORETTA R.; PETRIGH R.; ALCARAZ E.; DE ECHAIDE ST; FARBER M.
Lugar:
Montevideo
Reunión:
Simposio; 12º Simposio Internacional de la Asociación Mundial de Laboratorios de Diagnóstico Veterinario; 2005
Resumen:
MSP1 is a dimer of two structurally unrelated polypeptides, MSP1a and
MSP1b. MSP1a is encoded by a single copy gene (msp1a). Because of
different number of tandem repeats (28- or 29- aminoacids) located in
the amino-terminal portion of the protein presents a molecular weight
variation among isolates. The msp1a gene is conserved during acute and
persistent rickettsemia in cattle and also during multiplication in
ticks and has been used as a stable genetic marker for identification of
Anaplasma marginale isolates. Eighty different repeated forms have been
described from European, Australian, and American isolates. However,
only two Argentinian isolates (Salta and Virasoro) were analyzed so far.
In our study we describe 11 new repeats from different geographical
regions of Argentina including enzootic and non-enzootic regions. Short
nucleotide sequences repeated in tandem, microsatellite (up to 6
nucleotides) or minisatellite elements are very frequent in eukaryotic
organisms. The accumulating bacterial genomic data have revealed that
these elements are also frequent in bacteria. Moreover, tandem repeats
have potentially high variability in repeated units number allowing
great strain discrimination capacity. Two different minisatellite
elements were found after complete Anaplasma marginale genome analysis
using ?Tandem Repeat Finder? software. AMTR11 consists in an 11bp
sequence repeated up to 19 times while AMTR15 (15bp) is repeated up 13
to times in the several isolates analysed so far . Both minisatellites
are excluded from ORFs and AMTR11 seemed to have higher variability rate
than AMTR15. Furthermore, AMTR11 and AMTR15 showed higher polymorphism
than MSP1a. Finally, these studies suggest that the analysis of AMTR11
and AMTR15 minisatellites may provide a new tool to further discriminate
among Anaplasma marginale isolates.