JM: Two distal downstream enhancers direct expression of the human apolipoprotein E gene to astrocytes in the brain. J Neurosci 2001, 21:812-22. doi:10.1186/1750-1326-5-34 Cite this article as: Dieter and Estus: Isoform of APOE with retained intron 3; qua

Two distal downstream enhancers controlling astrocyte expression of the human apolipoprotein E (apoE) gene in the brain were identified by analysis of transgenic mice generated with various constructs of the apoE/C-I/C-IV/C-II gene cluster. In wild-type mice, the highest overall levels of apoE mRNA were found in astrocytes in the glomerular layer of olfactory bulbs and in Bergmann glia in the cerebellum. This pattern of expression was reproduced in transgenic mice expressing the entire human apoE gene cluster and also in transgenic mice expressing specific enhancer segments within the cluster. Expression of the human apoE transgene at these sites was specified by two enhancer domains: one enhancer is located 3.3 kb downstream of the apoE gene, and a duplication of this sequence is located 15 kb downstream of the apoE gene. Astrocyte enhancer activity was contained within 620 and 619 bp segments