C5 Initiates the Generation of the MAC

TLS Online TPP Program

#Id: 4003

#Unit 2. Cellular Organization

Full relaxation of the supercoils requires 1 nick/85 kb, thus identifying the average length of “closed” DNA. This region could comprise a loop or domain similar in nature to those identified in the bacterial genome called as metaphase scaffold.

TLS Online TPP Program

#Id: 4004

#Unit 2. Cellular Organization

S/MARs is a DNA sequence which is generally located between H1 and H3 binding sites.

TLS Online TPP Program

#Id: 4005

#Unit 2. Cellular Organization

Radial loops in metaphase chromosomes. In the radial loop model of metaphase chromosome organization, domains of 30 kb to 100 kb emanate from a central protein scaffold that spirals through the axis of each chromosome arm..

TLS Online TPP Program

#Id: 4007

#Unit 2. Cellular Organization

Matrix-associated regions (MARs) may be identified by characterizing the DNA retained by the matrix isolated in vivo (left) or by identifying the fragments that can bind to the matrix from which all DNA has been removed (right).

TLS Online TPP Program

#Id: 4009

#Unit 2. Cellular Organization

           

TLS Online TPP Program

#Id: 4011

#Unit 2. Cellular Organization

A surprising feature is the lack of conservation of sequence in MAR fragments. They are usually 70% A-T rich. cis-acting sites that regulate transcription are common, as are 5’ introns, and a recognition site for topoisomerase II is usually present in the MAR.