Assume all the necessary general and regulatory transcriptio

Assume all the necessary general and regulatory transcription factors are available and active,

1. If we are assessing transcription of two genes, one containing a promoter and the second containing a cis-acting element and an enhancer, but no promoter, which of the two will be transcribed more efficiently?

a) Gene 1

b) Gene 2

c) Both genes would be efficiently transcribed

d) Neither gene would be efficiently transcribe

Solution

Answer: d) Neither gene would be efficiently transcribe

Reason:

Insulators called as boundary elements that regulate the eukaryotic transcription in the DNA sequences that usually function to limit or to isolate the activity of an enhancer. These boundary elements often enable in providing a physical barrier in order to keep the enhancers from enhancing a wrong gene.

If we are assessing transcription of two genes, one containing a promoter and the second containing a cis-acting element and an enhancer, but no promoter, neither gene would be efficiently transcribe becauce enhancer is cis-acting required as transcription factor to promote gene expression further along with promoter (in case of gene-2, promoter is absent)

On the other hand, if gene -1 has only \"promoter\" and the remaining are absent so that this gene-1 will not leads to mRNA expression becuase cis-acting enhancers are essential,

Genetic code is degenerate & redundant. Initially specific ligands are going to bind to receptor (for example nuclear receptors) to activate specific gene expression via binding to \"transcription factors and RNA polymerase enzyme complex\" to \"specific region of DNA (enhancer region or promoter region)\" so that a particular mRNA codons (to code for sex hormones) are going to coded from the DNA template on complimetarity basis. Therefore, it is signaling molecule (ligand binding) determine the particular mRNA codon synthesis using enzyme complex.

A group of transcription factors assembles at the promoter region of DNA, and bind to TATA box (DNA sequence, a cis-regulatory element found in archae & eukaryotes), GC rich region, CAAT box to change its shape. This event exposes the binding sites of other transcription factors. After several of these events, RNA polymerase binds.

The binding of RNA polymerase to the promoter site starts the process of transcription by unzipping DNA. There are three different classes of RNA polymerases and they bind to different promoter sites and transcribe different parts of genome. Of these, RNA polymerase II causes the transcription of mRNA.