Question: please help answer this question please answer the three parts...
Please Help Answer This Question: Please answer the three parts A, B and C, I will vote well.
An early attempt to understand how the packaging of DNA into
eukaryotic transcription used a defined DNA template, purified RNA polymerase
II, and four general transcription factors – TFIIA, TFIIB, TFIID, and TFIIE.
If the template was first combined with nucleosomes and assembled into
chromatin, no transcription was detected when the transcription components
were added (see Figure below, lane 2).
If the template was first pre-incubated with the transcription components (in the
absence of NTPs, so that transcription was not possible at that time) and then
assembled into chromatin, followed by the purification of the chromatin template,
then the transcription proceeded just as well as on the naked DNA template
when the transcription components were added (compare lanes 1 and 3 on Fig.
below). This suggested that the transcription components, when first bound to
the template, keep the promoter accessible even in the presence of nucleosomes.
This phenomenon was investigated in more detail in two additional kinds of
experiments. In the first experiment, individual transcription components were
omitted during the pre-incubation (lanes 4 to 8). In the second, individual
components were omitted during the transcription assay (lanes 9 to 13).
A. Which of the transcription components must be present during
in order for the template to be active after chromatin assembly?
B. Which of the transcription components can form a complex with the template
that is stable enough to survive chromatin formation and subsequent purification?
C. Which of the transcription components must absolutely be added during the
transcription assay in order to produce a transcript?