Neumann, P., Navrátilová, A., Koblížková, A., Kejnovský, E., Hřibová, E., Hobza, R., Widmer, A., Doležel, J., Macas, J.
MOBILE DNA
2:
4,
2011
Klíčová slova:
Abstrakt:
Background: The centromeric and pericentromeric regions of plant chromosomes are colonized by Ty3/gypsy
retrotransposons, which, on the basis of their reverse transcriptase sequences, form the chromovirus CRM clade.
Despite their potential importance for centromere evolution and function, they have remained poorly
characterized. In this work, we aimed to carry out a comprehensive survey of CRM clade elements with an
emphasis on their diversity, structure, chromosomal distribution and transcriptional activity.
Results: We have surveyed a set of 190 CRM elements belonging to 81 different retrotransposon families, derived
from 33 host species and falling into 12 plant families. The sequences at the C-terminus of their integrases were
unexpectedly heterogeneous, despite the understanding that they are responsible for targeting to the centromere.
This variation allowed the division of the CRM clade into the three groups A, B and C, and the members of each
differed considerably with respect to their chromosomal distribution. The differences in chromosomal distribution
coincided with variation in the integrase C-terminus sequences possessing a putative targeting domain (PTD).
A majority of the group A elements possess the CR motif and are concentrated in the centromeric region, while
members of group C have the type II chromodomain and are dispersed throughout the genome. Although
representatives of the group B lack a PTD of any type, they appeared to be localized preferentially in the
centromeres of tested species. All tested elements were found to be transcriptionally active.
Conclusions: Comprehensive analysis of the CRM clade elements showed that genuinely centromeric
retrotransposons represent only a fraction of the CRM clade (group A). These centromeric retrotransposons
represent an active component of centromeres of a wide range of angiosperm species, implying that they play an
important role in plant centromere evolution. In addition, their transcriptional activity is consistent with the notion
that the transcription of centromeric retrotransposons has a role in normal centromere function.
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Autoři z ÚEB: Jaroslav Doležel,
Eva Hřibová
Čeština
English