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NBME 22 Answers
A 45-year-old man with Li-Fraumeni syndrome agrees ...
Decreased binding of RNA polymerase
Author rationale: "What is grammar?"
between increased or decreased binding I picked decreased because it was a mutation which affected the hydrogen bonds which is how nucleotides bind to each other
You said it, they are "trying" to ask. Should use better grammar.
From a random paper I found, “Arguably p53’s most important function is to act as a transcription factor that directly regulates perhaps several hundred of the cell’s RNA polymerase II (RNAP II)-transcribed genes.” So normally it increases RNA pol binding; a mutation would decrease it.
The TATA box is part of the promoter region site where RNA polymerase II and other transcription factors bind to DNA. A defect would therefore decrease binding of RNA polymerase.
Also you can reason it out (I got this wrong because you have to be really meticulous) since we know that loss of p53 = cancer. Cancer = want more cell division = don’t want inhibitory gene = less transcription of said gene.
It's talking about mutations on the transcription of genes that inhibit the cell division. Also RNA polymerase binds to the promoter region.
Also, the question specifically (though in a very wordy, convoluted way) asked what the effect of the mutation on transcription was. DNA pol is not used in transcription, it is used in replication. RNA pol is used in transcription. In terms of increased or decreased binding, argining is polar/positively charged and proline is neutral/nonpolar, so there are fewer H-bonding sites, and thus decreased binding of the RNA pol.
Could this convoluted question also mean..........
that since the gene to make p53 is messed up due to the hydrogen bonds, RNA polymerase will not be able to bind to make the mRNA ... So there will be cancer? Because P53 is a tumor suppressor... lemme know thanks guys