Describe the role of transcription factors, enhancers, silencers and promoters i

Question

Describe the role of transcription factors, enhancers, silencers and promoters in transcriptional regulation (p. 296 – 298, p. 300, p. 314 – 315) (Tablet p.324 – 326, p328, p.342 – 343) – Link transcription factors to Y2H system LO15 Describe the role of transcription factors, enhancers, silencers and promoters in transcriptional regulation (p. 296 – 298, p. 300, p. 314 – 315) (Tablet p.324 – 326, p328, p.342 – 343) – Link transcription factors to Y2H system LO15 Describe the role of transcription factors, enhancers, silencers and promoters in transcriptional regulation (p. 296 – 298, p. 300, p. 314 – 315) (Tablet p.324 – 326, p328, p.342 – 343) – Link transcription factors to Y2H system LO15

Explanation / Answer

In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence.The function of TFs is to regulate - turn on and off - genes in order to make sure that they are expressed in the right cell at the right time and in the right amount throughout the life of the cell and the organism. Groups of TFs function in a coordinated fashion to direct cell division, cell growth, and cell death throughout life; cell migration and organization (body plan) during embryonic development; and intermittently in response to signals from outside the cell, such as a hormone. There are up to 2600 TFs in the human genome.

ROLE OF ENHANCER

In genetics, an enhancer is a short (50–1500 bp) region of DNA that can be bound by proteins (activators) to increase the likelihood that transcription of a particular gene will occur These proteins are usually referred to as transcription factors. Enhancers are cis-acting. They can be located up to 1 Mbp way from the gene, upstream or downstream from the start site.There are hundreds of thousands of enhancers in the human genome.They are found in both prokaryotes and eukaryotes.

The first discovery of a eukaryotic enhancer was in the immunoglobulin heavy chain gene in 1983.This enhancer, located in the large intron, provided an explanation for the transcriptional activation of rearranged Vh gene promoters while unrearranged Vh promoters remained inactive.

Role of Silencer

a silencer is a DNA sequence capable of binding transcription regulation factors, called repressors. DNA contains genes and provides the template to produce messenger RNA (mRNA). That mRNA is then translated into proteins. When a repressor protein binds to the silencer region of DNA, RNA polymerase is prevented from transcribing the DNA sequence into RNA. With transcription blocked, the translation of RNA into proteins is impossible. Thus, silencers prevent genes from being expressed as proteins.

RNA polymerase, a DNA-dependent enzyme, transcribes the DNA sequences, called nucleotides, in the 3' to 5' direction while the complementary RNA is synthesized in the 5' to 3' direction. RNA is similar to DNA, except that RNA contains uracil, instead of thymine, which forms a base pair with adenine. An important region for the activity of gene repression and expression found in RNA is the 3' untranslated region. This is a region on the 3' terminus of RNA that will not be translated to protein but includes many regulatory regions.

Not much is yet known about silencers but scientists continue to study in hopes to classify more types, locations in the genome, and diseases associated with silencers

Promotors

Promoter is a region of DNA that initiates transcription of a particular gene. Promoters are located near the transcription start sites of genes, on the same strand and upstream on the DNA (towards the 5' region of the sense strand). Promoters can be about 100–1000 base pairs long.

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.