Structure and dynamics of retrotransposons at wheat centromeres and pericentromeres
- 719 Downloads
Little is known of the dynamics of centromeric DNA in polyploid plants. We report the sequences of two centromere-associated bacterial artificial chromosome clones from a Triticum boeoticum library. Both autonomous and non-autonomous wheat centromeric retrotransposons (CRWs) were identified, both being closely associated with the centromeres of wheat. Fiber-fluorescence in situ hybridization and chromatin immunoprecipitation analysis showed that wheat centromeric retrotransposons (CRWs) represent a dominant component of the wheat centromere and are associated with centromere function. CRW copy number showed variation among different genomes: the D genome chromosomes contained fewer copies than either the A or B genome chromosomes. The frequency of lengthy continuous CRW arrays was higher than that in either rice or maize. The dynamics of CRWs and other retrotransposons at centromeric and pericentromeric regions during diploid speciation and polyploidization of wheat and its related species are discussed.
KeywordsBacterial Artificial Chromosome Long Terminal Repeat Bacterial Artificial Chromosome Clone Bacterial Artificial Chromosome Library Pericentromeric Region
The authors are grateful to Dr. J. Jiang (University of Wisconsin, Madison, USA) for providing the RCS1 plasmid and valuable comments on the manuscript, to Dr. S. Henikoff (Fred Hutchinson Cancer Research Center) for the rice CENH3 antibody, to Dr. C. Feuillet (INRA, Clermont-Ferrand, France) for providing the 3B centromere-associated BAC clones, to J. Wu (ICS, CAAS) for help with the BAC sequencing and bioinformatic analysis, and to Z. Cheng and L. Mao (ICS, CAAS) for valuable discussion. They also thank www.smartenglish.co.uk for linguistic advice in the preparation of this manuscript. This research was supported by the Natural Science Foundation of China (39870494, 30771208).
- Chen F, Zhang X, Xia G, Jia J (2002) Construction and characterization of a bacterial artificial chromosome library for Triticum boeoticum. Acta Bot Sinica 44:451–456Google Scholar
- Lim KB, Yang TJ, Hwang YJ, Kim JS, Park JY, Kwon SJ, Kim J, Choi BS, Lim MH, Jin M, Kim HI, de Jong H, Bancroft I, Lim Y, Park BS (2007) Characterization of the centromere and peri-centromere retrotransposons in Brassica rapa and their distribution in related Brassica species. Plant J 47:173–183Google Scholar
- McFadden ES, Sears ER (1944) The artificial synthesis of Triticum spelta. Rec Genet Soc Am 13:26–27Google Scholar
- Nagaki K, Song J, Stupar RM, Parokonny AS, Yuan Q, Ouyang S, Liu J, Hsiao J, Jones KM, Dawe RK, Buell CR, Jiang J (2003a) Molecular and cytological analyses of large tracks of centromeric DNA reveal the structure and evolutionary dynamics of maize centromeres. Genetics 163:759–770PubMedGoogle Scholar
- Rayburn AL, Gill BS (1986) Molecular identification of the D-genome chromosomes of wheat. J Hered 77:253–255Google Scholar
- Yan H, Ito H, Nobuta K, Ouyang S, Jin W, Tian S, Lu C, Venu RC, Wang GL, Green PJ, Wing RA, Buell CR, Meyers BC, Jiang J (2005) Genomic and genetic characterization of rice Cen3 reveals extensive transcription and evolutionary implications of a complex centromere. Plant Cell 18:2123–2133CrossRefGoogle Scholar