Question

Describe and outline the structural components of a gene, include all regulatory regions that can impact transcription initiation. Then add the chromatin structure, making sure to describe the structure and role of the nucleosome. Now, describe the process of how a gene is actively expressed starting with transcription initiation and ending with a protein product (be specific about each step). Lastly, describe three different mechanisms of regulation of this process and the possible outcomes of each.

Answer 1

Gene is a part of DNA , which transcribed in to RNA then protein and produce effect  

A typical gene contains following structure

1) promoter - is the site where RNA polymerase binds and start transcribing gene and present at 5' end of gene.

Made up of core promoter and promoter proximal elements.

2) open reading frame ( ORF) - is the actual part which transcribed in to TNA

3) terminator - site where, DNA polymerase deattach, completion of transcription. Present at 3' end of gene.

Some regulatory sequence present, which regulates expression of that gene. These may be located at 5 end of gene. .

Promoter proximal elements- locates near to the promoter.

Distal regulatory elements- located  many kilobases includes enhancers and silencers.

Core promoterbinds to Polymeraseand mark the site of transcription. . The proximal promoter region binds transcription factors that modify the affinity of the core promoter for RNA polymerase.

Further regulation if gene expression may be regulated by multiple enhancer and silencer sequences .

Enhancers- binds with activator protein, activate transcripton of gene.

Silencer - binds with repressor and repress gene expression.

Thus binding of different transcription factors, regulates the rate of transcription initiation at different times and in different cells.

A typical gene structure has been attached below

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