+
Related Flashcards
Related Topics
Cards In This Set
| Front | Back |
|
Chromatin compaction wrapping DNA about histone cores to form nucleosome
|
Accomplishes part of the compaction necessary to fit the long eukaryotic DNA into the nucleus
|
|
However much of the chromatin in the nucleus is
|
Even more highly compacted
|
|
The next stage in compaction involves
|
Folding the beaded fiber into thicker fiber
|
|
These fibres may be further folded on themselves to make
|
Thicker chromatin fibres visible in both metaphase chromosomes and nuclei of non dividing (interphase) cells
|
|
Metaphase scaffolding dye staining of metaphase chromosome from a particular organism
|
Gives a reproducible banding pattern
|
|
In situ hybridisation methods show that
|
Particular DNA sequence are always located at the same places in specific chromosomes
|
|
Some kind of regular folding
|
Must preserve this order
|
|
Recent evidence indicates that when
|
Metaphase chromosomes are treated with polyanions to strip off histones and loosely bound non histone proteins
|
|
The DNA strands emerge as enormous loops
|
From a scaffold to tightly bound protein
|
|
Individual loops may range up to
|
100000 bp in length....about the size of glob in gene cluster
|
|
For eg appx 1000 such loops exist in the
|
Average chromosome
|
|
Interphase scaffolding evidence also exists for a similar but more
|
Diffuse scaffold in the interphase nucleus
|
|
Removal of histones and weekly bound non histone proteins from intact nuclei by
|
High salt conc or detergents
|
|
Together with digestion of most of the DNA by nucleases
|
Leaves a protein structure that has been called nuclear scaffold or nuclear matrix
|
|
It includes the laminar shell that lines inside of the
|
Nuclear membrane
|
