Epigenetic regulation of centromeric chromatin: old dogs, new tricks?

The assembly of just a single kinetochore at the centromere of each sister chromatid is essential for accurate chromosome segregation during cell division. Surprisingly, despite their vital function, centromeres show considerable plasticity with respect to their chromosomal locations and activity. The establishment and maintenance of centromeric chromatin, and therefore the location of kinetochores, is epigenetically regulated. The histone H3 variant CENP-A is the key determinant of centromere identity and kinetochore assembly. Recent studies have identified many factors that affect CENP-A localization, but their precise roles in this process are unknown. We build on these advances and on new information about the timing of CENP-A assembly during the cell cycle to propose new models for how centromeric chromatin is established and propagated

Long-distance transporters of inorganic nutrients in plants

In plants, long-distance transport of inorganic nutrients is important for mineral nutrition, ion homeostasis, nutrient recycling, and the detoxification of toxic or excess inorganic ions. Here, we review information on the transporters involved in the loading/unloading of inorganic nutrients to and from the vascular bundle. We also describe the methods used to obtain such information.X118sciescopuskc

Localization of DNA sequences required for human centromere function through an analysis of rearranged Y chromosomes.

We have localized the DNA sequences required for mitotic centromere function on the human Y chromosome. Analysis of 33 rearranged Y chromosomes allowed the centromere to be placed in interval 8 of a 24-interval deletion map. Although this interval is polymorphic in size, it can be as small as approximately 500kb. It contains alphoid satellite DNA and approximately 300kb of adjacent Yp sequences. Chromosomes with rearrangements in this region were analysed in detail. Two translocation chromosomes and one monocentric isochromosome had breakpoints within the alphoid array. Of 12 suppressed Y centromeres on translocation chromosomes and dicentric isochromosomes that were also analysed two showed deletions one of which only removed alphoid DNA. These results indicate that alphoid DNA is a functional part of the Y chromosome centromere