Explain three example mechanisms of how a cell could increase / decrease the amount of RNA or protein coming from a gene- how does each mechanism work?

Answer 1

Transcription activating factors (TAFs) could bind to the promoter/enhancer region of the gene. These proteins change the conformation or structure of the DNA sequence where RNA polymerase binds to begin transcription, so there would be an increase in the amount of mRNA produced. That in turn could lead to more protein. Alternatively, suppressor proteins could bind the same region, making the start site for transcription less accessible, yielding decreased mRNA and less protein.

The length of the poly A tail can also be altered. A longer ploy A tail would give the mRNA more stability, and a shorter poloy A tail would make it less stable. A more stable mRNA could be used for multiple rounds of translation, producing more protein. A less stable mRNA would be degraded faster, and not be as availble for multiple translation events, so there would be less protein.

The rate of translation can also vary. A single mRNA can be attached to multiple ribosomes, with all of them producing protein simultaneously. The more ribosomes that are bound to the mRNA, the more protein would be produced.

Hope this helps.