Transgenic mice do not express endogenous mouse apolipoprotein E (APOE). The expression pattern of the transgenic human apolipoprotein E2 isoform (APOE2) follows the endogenous mouse APOE and GFAP expression patterns in the brain. Human APOE2 is immunodetectable in glia and neuropil in developing and adult mutant mice. Cultured astrocytes from transgenic mice secrete APOE2 in lipoproteins that are similar in size to high density plasma lipoproteins (HDL). Detergent-soluble APOE2 protein levels in forebrain tissue from hemizygous mice and in adult human cortex tissue are similar.

Mice that are hemizygous or homozygous for the transgenic insert and homozygous for Apoe^tm1Unc are viable, normal in size, and do not display any gross physical or behavioral abnormalities.