Question

1. During eukaryotic transcription, TFIID recognizes and binds the ____ box in the DNA.
2. The technique initially used in the identification of promoter sequences was ________________.
3. A more contemporary technique for identification of promoter sequences is the _________ _____________________ assay.

Answer 1

1. Answer:TATA

• The E. coli RNA polymerase (σ subunit), recognizes and binds to the -35 site. Followed by enzyme interaction and DNA unwinding at the -10 region.
• Eukaryotic promotor is tripartite, consisting of- GC box, CAT, TATA box. Initiation requires binding of transcriptional factors, like TFIIA, TFIIB, etc, binding to TATA box.
• CTD is C-terminal domain of enzyme RNA polymerase II.

2. Answer: DNA foot printing

• For detection of DNA/ protein interaction.
• The protein that is bound to DNA protect it from enzymatic cleavage.
• The DNA sample are treated with enzyme deoxyribonuclease or DNase, that cleave radio-labelled DNA. The samples are then run through electrophoretic process. The DNA sample that are protected by enzyme, do not under go cleavage and is represented as gap on the gel, termed as foot print.
• Similarly polymerase protein binding to DNA for transcription could be traced using DNA foot printing.

3. Answer: Chromatin immunoprecipitation

• Another technique used for detection of protein-DNA interaction is chromatin immunoprecipitation.
• For the purpose of immunoprecipitation, antigen corresponding to the protein to be detected is associated with the chromatin and the corresponding sequence is studies for the reaction.