The
Thymocyte progenitors enter the subcapsular region of the thymus as
double-negative cd3- t cells where the double negative refers to lack of
cluster determinants CD4 and CD8. Double-negative cd3- t cells exist as small population
that is 1%-5% of lymphocytes in the lymphoid organs and peripheral blood of
humans and normal rodents.
Answer:
A. The chromatin near cis-regulatory sequences will be more closed and there will be less transcription.
Explanation:
In the presence of histones, the cis-regulatory sequences of DNA like promoter, enhancers etc. are not exposed. The function of the histone acetyltransferases (HATS) is to cause chromosome decondensation i.e. removal of histones from the DNA so that transcription of the DNA could occur. Histone acetyltransferases (HATS) cause acetylation of lysine amino acid of the histone proteins. Acetyl group is negatively charged so the acetylation of histone proteins leads to the removal of their positive charge which ultimately leads to the decrease in the interaction between N terminal of histones and negatively charged phosphate group of the DNA molecule. As soon as histones are removed from the DNA where cis-regulatory sequences are located, the DNA becomes accessible for transcription.
But here a drug has been added which blocks the activity of histone acetyltransferases (HATS) in cancer cells. So it is quite evident that in these cells, histones will not get removed from the cis-regulatory sequences of DNA so the DNA will be more closer or tightly packed as a result of which less transcription will occur.
Answer:
The answer would be A. Increase
