Sequential centromere shift via de novo formation in maize

ABSTRACT: The ability of centromeres to alternate between active and inactive states indicates significant epigenetic elements controlling centromere assembly and centromere function. In maize (Zea mays), misdivision of the B chromosome centromere on a translocation with the short arm of chromosome 9 (TB-9Sb) can produce many variants with varying centromere sizes and centromeric DNA sequences. In derivatives of TB-9Sb, we found a de novo centromere on chromosome telo-3-3, which has no canonical centromeric repeat sequences. This centromere is derived from a 288-kb region on the short arm of chromosome 9, and is 19 megabases (Mb) removed from the translocation breakpoint of chromosome 9 in TB-9Sb. This centromere is much smaller than normal ones but can be maintained through meiosis. The functional B centromere in progenitor telo2-2 is deleted from telo3-3 but some B-repeat sequences remain. The de novo centromere of telo3-3 becomes inactive in three further derivatives with new centromeres being formed elsewhere on the chromosomes. One such de novo centromere contains only 200-kb CENH3 binding domain. This 200-kb centromere is located 3 Mb removed from the translocation breakpoint in a new location. The deleted B centromere in telo3-3 is activated in two derivatives. Our results suggest that de novo centromere formation is more common than previously thought and can persist on chromosomal fragments without a canonical centromere providing implications for karyotype evolution. ChIP-seq was carried out with anti-CENH3 antibodies using material from young leaves with control, telo3-3 and its derivate.

ORGANISM(S): Zea mays

SUBMITTER: Handong Su 

PROVIDER: E-GEOD-59124 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress