Stability of monocentric and dicentric ring minichromosomes in Arabidopsis

作者：Yokota Etsuko; Shibata Fukashi; Nagaki Kiyotaka; Murata Minoru^*

来源：Chromosome Research, 2011, 19(8): 999-1012.

DOI：10.1007/s10577-011-9250-3

• Arabidopsis
• Centromere
• Minichromosome
• Ring chromosome
• Stability

A dicentric ring minichromosome (mini delta) was identified in transgenic Arabidopsis thaliana and added to a wild type as a supernumerary chromosome. This line is relatively stable and has been maintained for generations, notwithstanding its ring and dicentric structure. To determine the mechanism for stable transmission of mini delta, the structure and behavior of two new types of ring minichromosomes (mini delta 1 and mini delta 1-1) derived from mini delta were investigated. Fluorescence in situ hybridization analysis revealed that mini delta 1 is dicentric just like mini delta, whereas mini delta 1-1 is monocentric. The estimated sizes of mini delta 1 and mini delta 1-1 were 3.8 similar to 5.0 and 1.7 Mb, respectively. The sizes of the two centromeres on mini delta 1 were identical (ca. 270 kb) and similar to that of mini delta 1-1 (ca. 250 kb). Mini delta 1 was relatively stable during mitosis and meiosis, as is mini delta, whereas mini delta 1-1 was unstable during mitosis, and the number of minichromosomes per cell varied. This possibly resulted from misdivision caused by a short centromere on monocentric mini delta 1-1. Transmission through the female was quite limited for all three ring minichromosomes (0-3.2%), whereas that through the male was relatively high (15.4-27.3%) compared with that of other supernumerary chromosomes in Arabidopsis. Ring structure without telomeres itself seems not to limit the female transmission.

• 出版日期2011-11