The transcription of a gene called YFG (your favoritegene) is activated when three transcription factors (TFA,TFB, TFC) interact to recruit the co-activator CRX. TFA,TFB, TFC, and CRX and their respective binding sitesconstitute an enhanceosome located 10 kb from the transcription start site. Draw a diagram showing how youthink the enhanceosome functions to recruit RNA polymerase to the promoter of YFG.

Gal4 is a transcription factor that activates transcription of galactose metabolism genes in yeast. These genes are ‘turned on’ when yeast cells need to metabolize galactose. To identify promoter sequences necessary for regulation of transcription of GAL1, reporter gene fusions were made and introduced into yeast cells. Deletions of GAL1 promoter were cloned upstream of LacZ gene. β-Galactosidase activity was measured in presence of galactose. Shown below is a representation of the results obtained. In the diagrams below (not to scale!): • Construct 1 contains ~ 130bp of the promoter, which is predicted to have all the predicted/putative proximal promoter elements (indicated by the solid boxes) needed to regulate transcription of GAL1.• The stippled box is the core promoter.• The arrow represents the transcriptional start site for the reporter gene Lac Z• Number of + signs represents level of transcription• Star represents a mutation in DNA sequence at that location (few nucleotides…

Many viruses that infect eukaryotic cells express genes that alterthe regulation of host gene expression to promote viral replication.For example, herpes simplex virus-1 (HSV-1) expresses aprotein called ICP0, which is necessary for successful viral infectionand replication within the host. Lutz et al. (2017. Viruses9: 210) showed that ICP0 can act as a ubiquitin ligase and targetthe redundant transcriptional repressors ZEB1 and ZEB2,which leads to upregulation of the miR-183 cluster (a set of threemiRNAs transcribed from the same locus). How may ICP0 expression in a host cell lead to upregulationof the miR-183 cluster?

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