Figure 5.

Mediator in metazoans. (a) Essentiality of Mediator subunits in Drosophila derived from a CRISPR screen; highlighted subunits were deemed likely to be essential [89]. (b) Mediator subunits labeled according to whether they are essential in yeast or likely to be haploinsufficient in humans, based on data from gnomAD [83]. (c) The paralogs Med12 and Med12L from the kinase module may have distinct nuclear localization. Left, Med12 stained green and microtubules stained red shows Med12 in the nucleoplasm; right, Med12L stained green, nucleus stained blue and microtubules stained red indicate that Med12L is localized to nucleoli (images from the Human Protein Atlas (https://www.proteinatlas.org/search/med12) [90]), which may suggest a special role for Med12L in regulating Pol II in the nucleolus [91].