Figure 9.
A “two-switch” model for the control of neuronal expression of apoE. The first switch, transcription of the apoE gene, is constitutively on and generates apoE-I3 under normal conditions. The apoE-I3 is retained in the nucleus and is not translated. The second switch, the processing of apoE-I3 into mature apoE mRNA, is turned on in response to neuronal injury.