title: Structural features of the rice chromosome 4 centromere.
abstract: A complete sequence of a chromosome centromere is necessary for fully understanding centromere function. We reported the sequence structures of the first complete rice chromosome centromere through sequencing a large insert bacterial artificial chromosome clone-based contig, which covered the rice chromosome 4 centromere. Complete sequencing of the 124-kb rice chromosome 4 centromere revealed that it consisted of 18 tracts of 379 tandemly arrayed repeats known as CentO and a total of 19 centromeric retroelements (CRs) but no unique sequences were detected. Four tracts, composed of 65 CentO repeats, were located in the opposite orientation, and 18 CentO tracts were flanked by 19 retroelements. The CRs were classified into four types, and the type I retroelements appeared to be more specific to rice centromeres. The preferential insert of the CRs among CentO repeats indicated that the centromere-specific retroelements may contribute to centromere expansion during evolution. The presence of three intact retrotransposons in the centromere suggests that they may be responsible for functional centromere initiation through a transcription-mediated mechanism.
authors.affiliation: National Center for Gene Research, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 500 Caobao Road, Shanghai 200233, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Huang
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Tingting
authors.initials: T
authors.lastname: Lu
authors.forename: Yiqi
authors.initials: Y
authors.lastname: Lu
authors.forename: Qi
authors.initials: Q
authors.lastname: Feng
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhao
authors.forename: Zhukuan
authors.initials: Z
authors.lastname: Cheng
authors.forename: Yongbiao
authors.initials: Y
authors.lastname: Xue
authors.forename: Rod A
authors.initials: RA
authors.lastname: Wing
authors.forename: Bin
authors.initials: B
authors.lastname: Han
mesh_terms: D001483:Base Sequence; D002503:Centromere / Q000737:chemistry*; D022202:Chromosomes, Artificial, Bacterial; D032461:Chromosomes, Plant / Q000737:chemistry*; D004276:DNA, Satellite / Q000737:chemistry; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics*; D020161:Physical Chromosome Mapping; D018626:Retroelements; D017422:Sequence Analysis, DNA; D020080:Tandem Repeat Sequences
chemical_list: D004276:DNA, Satellite; D018626:Retroelements