Question

The genetic term “loss of function” is used to describe any mutation in the DNA that leads to a particular protein that cannot function. There are many reasons why a protein may not be functioning any longer…digging into your knowledge on the mechanism of gene expression and gene expression regulation, describe a mutation that could lead to a loss of function mutation. Where is the mutation in the gene? What function of gene expression or gene expression regulation is it affecting? How is it leading to a loss of function for the protein encoded for within that gene?

But I’m going to restrict your answer…describe a mechanism that DOES NOT include a point mutation leading to missense, nonsense, or frameshift – in other words, choose a mutation/mechanism other than a mutation that leads to a change in the protein-coding region of a mature mRNA. I want you to think outside of that particular box.

Answer 1

Transcription is controlled by RNA polymerase and number of transcription factors. These transcription factors are proteins. Mutation in the DNA where the transcription factors bind can also lead to loss of function and mutation in the transcription factor itself also can cause loss of function. This is because unless the TF are attached to the DNA transcription does not occur. This can result in loss of function mutation.

TATA binding protein (TBP) is a protein in Eukaryotes which attaches to the TATA box in the promoter region of the DNA molecule and bends the DNA to bring transcription factors attached to enhancer and core promoter regions together. Any mutation in the DNA where the TBP binds prevents it from binding preventing it from  bringing the enhancer and the core promoter regions together. This does not produce mRNA for the protein and can lead to loss of function mutation.