Question

When friend erythroleukemic cells are incubated with sodium butyrate, they differentiate into nondividing, hemoglobin-synthesizing cells. Butyrate-induce differentiation is accompanied by accumulation of acetylated forms of H3 and H4 histones, as can be seen most clearly for H4 in figure 4-16A. In principle, butyrate treatment could increase the activity of histone acetyl transferases (HATs) or decrease the activity of histone deacetylase complexes (HDACs). To distinguish between these alternatives, HAT and HDAC activities were measured in the presence and absence of butyrate (figure 4-16B and C). From these results decide how butyrate treatment causes accumulation of acetylated histones.

Answer 1

Respuesta:

It is impossible to know how many cells there are in an average man (170 cm tall and 70 Kg in weight). 30 billion? In any case, a figure hardly imaginable. Most of these "cells" are red blood cells (erythrocytes) that should not be considered as such sensu stricto, as they lack a nucleus. In all other cells, the nucleus contains 46 chromosomes (23 duplicated chromosomes). Each chromosome is made up of a strand of DNA associated with proteins (histones). If each strand of DNA were "stretched out" completely, it would be about 1 meter in length. However, the DNA strands remain constrained in the tiny space of the cell nucleus, taking up one billionth of their length if they were "stretched out."