Mice, KnockoutPhenotypeGene Knockout TechniquesMice, Inbred C57BLResearch PersonnelDisease Models, AnimalMice, TransgenicGene TargetingGene DeletionSignal TransductionMice, 129 StrainCells, CulturedBiomedical ResearchGene Expression RegulationRNA, MessengerBehavior, AnimalBrainLiverApolipoproteins EReverse Transcriptase Polymerase Chain ReactionTime FactorsNeuronsImmunohistochemistry