A molecular architecture is proposed for an example mitotic chromosome, human Chromosome 10. This architecture is built on a previously described interphase chromosome structure based on Cryo-EM cellular tomography (1), thus unifying chromosome structure throughout the complete mitotic cycle. The basic organizational principle, for mitotic chromosomes, is specific coiling of the 11-nm nucleosome fiber into large scale approximately 200 nm structures (a Slinky (2, motif cited in 3) in interphase, and then further modification and subsequent additional coiling for the final structure. The final mitotic chromosome architecture accounts for the dimensional values as well as the well known cytological configurations. In addition, proof is experimentally provided, by digital PCR technology, that G1 T-cell nuclei are diploid, thus one DNA molecule per chromosome. Many nucleosome linker DNA sequences, the promotors and enhancers, are suggestive of optimal exposure on the surfaces of the large-scale coils.
Regulation of mitotic chromosome architecture and resolution of ultrafine anaphase bridges by PICH
