Question

2. For each of the following sentences, fill in the blanks with the best word or phrase in the list below. Not all words or phrases will be used; use each word or phrase only once During transcription in __________________ cells, transcriptional regulators that bind to DNA thousands of nucleotides away from a gene’s promoter can affect a gene’s transcription. The __________________ is a complex of proteins that links distantly bound transcription regulators with the proteins bound closer to the transcriptional start site. Transcriptional activators can interact with histone __________________s, which alter chromatin by modifying lysines in the tail of histone proteins to allow greater accessibility to the underlying DNA. Transcription regulators can also recruit _______________________ to the promoter region of a gene, causing the DNA packaged in chromatin more accessible to proteins required for ___________________.

Options:

viral acetyltransferase centrosome helicase chromatin-remodeling complexes procaryotic peroxidase eucaryotic Mediator deoxidase heterochromatin telomere enhancer leucine zipper transcription initiation translation initiation transcription elongation translation termination

Answer 1

During transcription in _____EUKARYOTIC____ cells, transcriptional regulators that bind to DNA thousands of nucleotides away from a gene’s promoter can affect a gene’s transcription. The ___chromatin-remodeling complexes_____ is a complex of proteins that links distantly bound transcription regulators with the proteins bound closer to the transcriptional start site. Transcriptional activators can interact with histone ____acetyltransferase___s, which alter chromatin by modifying lysines in the tail of histone proteins to allow greater accessibility to the underlying DNA. Transcription regulators can also recruit ___enhancer__ to the promoter region of a gene, causing the DNA packaged in chromatin more accessible to proteins required for _____transcription_____.

Regulators, enhancers etc molecules are present only in the regulation of gene expression in eukaryotic cells.

There are molecules which bind with the nucleosome-free region of DNA and acts on the target DNA to increase its accessibility so that transcription machinery can attach to the area.

The next step is to some epigenetic modification, where there is the acetylation of the histone protein. Acetylation neutralizes the positive charge on histone protein and causes relaxation of the DNA and there is no interaction with the negative charge of DNA.
There are few molecules known as enhancer which binds with the DNA in the vicinity of the promoter region or away from the promoter. They are known as cis acting element. They are to enhance the binding of RNA polymerase to initiate transcription.