A Proposed Unified Interphase Nucleus Chromosome Structure: Preliminary Preponderance of Evidence

Abstract

Cellular cryo-electron tomography (CET) of the cell nucleus using Scanning Transmission Electron Microscopy (STEM) and the use of deconvolution (DC) processing technology has highlighted a large-scale, 100-300 nm interphase chromosome structure (LSS), that is present throughout the nucleus. This chromosome structure appears to coil the nucleosome 11-nm fiber into a defined hollow structure, analogous to a Slinky (S) (1, motif used in 2) helical spring. This S architecture can be used to build chromosome territories, extended to polytene chromosome structure, as well as to the structure of Lampbrush chromosomes.

A proposed unified mitotic chromosome architecture

“…We tried to use the interphase chromosome Slinky structure that had been described ( 1 ) to model, by coiling this structure into a dimensioned human chromosome 10 mitotic chromosome. We used the coiling software described in Materials and Methods .…”

“…Packing the DNA of a given chromosome, with multiple centimeters of DNA for an average human chromosome ( 1 – 3 ), into a mitotic chromosome some microns in length requires a length compression of 10 to 20,000, a challenging problem. There are many models for mitotic chromosome architecture (reviewed in refs.…”

“…The proposed mitotic chromosome architecture is built on an interphase chromosome architecture ( 1 ). In brief, a scanning transmission electron microscopy cryo-electron microscopy (cryo-EM) nucleus tomogram, preserving the interphase nuclear structures by the cryo procedures and then suitably processed by deconvolution ( 1 , 8 – 10 ) was made. Throughout the nucleus, a 100- to 300-nm coiled nucleosome 11-nm fiber was documented.…”

“…Fig. 1 summarizes the interphase chromosome structure. First, human chromosome 10 DNA is depicted in Fig.…”

“…This paper uses a package of software, described in Materials and Methods , to sequentially coil multiple helices for quantitative modeling as a tool to explore mitotic chromosome architecture. This tool was also used in the interphase chromosome structure studies ( 1 ). The software models to an accurate (molecular) scale.…”