Question

In eukaryotes, miR-5 is a microRNA with sequence complementarity to the 3 UTR of the mRNA transcript encoded by the UCD gene. The UCD gene encodes for a protein that acts as an allosteric activator of the protein p101. The p101 protein is a histone acetyl transferase (HAT) which is an enzyme that acetylates histones when the protein is in its active form In a lung cancer cell line, the p101 protein is overly active leading to misregulation of gene expression. In these lung cancer cells which of the following would be a correct prediction in regards to miR-52 [choose ALL that apply, note that incorrect selections will deduct points The gene encoding miR-5 is in a region of chromatin with increased DNA methylation The gene encoding miR-5 is in a region with decreased DNA methylation The gene encoding miR-5 is in a region of euchromatin The gene encoding miR-5 is in a region of heterochromatin The miR-5 transcript is translated at high levels The miR-5 transcript is activating translation of the UCD gene A different lung cancer cell line is found to have significantly decreased amounts of histone acetylation. Which of the following could explain why there is decreased histone acetylation in this cell line? (choose ALL that apply, note that incorrect selections will deduct points) increased translation of the p101 protein due to low levels of miR-5 decreased translation of the p101 protein due to high levels of miR-5 increased translation of the UCD protein due to high levels of miR-5 decreased translation of the UCD protein due to low levels of miR-5 decreased translation of the UCD protein due to high levels of miR-5 the absence of the p101 protein due to miR-5 inhibiting transcription of the p101 mRNA transcript the absence of the UCD protein due to miR-5 inhibiting transcription of the UCD mRNA transcript

Answer 1

miR5 ----| UCD ------> p101 (HAT)

1. Options 1 and 4 are correct
The p101 protein is over-expressed i.e. miR5 should be repressed
i. Methylated DNA = Repressed gene
ii. False
iii. False: Euchromatin = Transcriptionally active
iv. True: Heterochromatin = Transcriptionally inactive
v. False: miR5 is a noncoding gene. It does not make a protein
vi. False: miR5 is a negative regulator of UCD gene