Transcriptional Elongation Factor Elongin A Regulates Retinoic Acid-Induced Gene Expression during Neuronal Differentiation

SummaryElongin A increases the rate of RNA polymerase II (pol II) transcript elongation by suppressing transient pausing by the enzyme. Elongin A also acts as a component of a cullin-RING ligase that can target stalled pol II for ubiquitylation and proteasome-dependent degradation. It is not known whether these activities of Elongin A are functionally interdependent in vivo. Here, we demonstrate that Elongin A-deficient (Elongin A−/−) embryos exhibit abnormalities in the formation of both cranial and spinal nerves and that Elongin A−/− embryonic stem cells (ESCs) show a markedly decreased capacity to differentiate into neurons. Moreover, we identify Elongin A mutations that selectively inactivate one or the other of the aforementioned activities and show that mutants that retain the elongation stimulatory, but not pol II ubiquitylation, activity of Elongin A rescue neuronal differentiation and support retinoic acid-induced upregulation of a subset of neurogenesis-related genes in Elongin A−/− ESCs.

Graphical AbstractFigure optionsDownload as PowerPoint slideHighlights
► RA-induced neuronal differentiation is markedly impaired in Elongin A−/− ESCs
► Formation of cranial ganglia and DRG is severely impaired in Elongin A−/− embryos
► Mutations that differentially affect the two activities of Elongin A were identified
► Elongin A’s elongation stimulatory activity is required for a subset of RA-induced genes