. Author manuscript; available in PMC: 2014 Sep 11.

Published in final edited form as: Nat Rev Cancer. 2013 Jan 10;13(2):83–96. doi: 10.1038/nrc3430

Table 2. Phenotypes of mice with modifications at the Mdm2 and Mdmx loci.

Tissue	Genotype	p53 regulation strategy^*	Phenotype^‡	Refs
CNS	Mdm2^-/-	Nestin-Cre;Trp53^LSL/-	Embryonic lethal; apoptosis	24
	Mdmx^-/-	Nestin-Cre;Trp53^LSL/-	Apoptosis and arrest	24
	Mdm2^FM/FM	Nestin-Cre	Embryonic lethal; apoptosis	109
	Mdmx^FX/FX	Nestin-Cre	Embryonic lethal; apoptosis and arrest	109
	Mdm2^-/-	Trp53^ER/-	No effect	81
	Mdmx^-/-	Trp53^ER/-	Apoptosis only in SVZ	81
Intestine	Mdm2^FM/FM	Villin-Cre	Apoptosis	164
	Mdmx^FX/FX	Villin-Cre	Apoptosis in proliferating cells	165
	Mdm2^-/-	Trp53^ER/-	Apoptosis	81
	Mdmx^-/-	Trp53^ER/-	Apoptosis	85
Smooth muscle	Mdm2^FM/FM	Sm22-CreER^T2	Cell death	166
Smooth muscle	Mdmx^FX/FX	Sm22-CreER^T2	No effect	166
Erythrocyte	Mdm2^lox/lox	EporGFP-Cre/+	Embryonic lethal; apoptosis	167
Erythrocyte	Mdmx^lox/lox	EporGFP-Cre/+	Arrest only in fetal erythropoiesis	167
Heart	Mdm2^FM/-	Myhc-Cre	Embryonic lethal; apoptosis	168
	Mdmx^FX/-	Myhc-Cre	Apoptosis	169
	Mdm2^-/-	Trp53^ER/-	No effect	81
	Mdmx^-/-	Trp53^ER/-	No effect	85
Thymus and spleen	Mdm2^-/-	Trp53^ER/-	Apoptosis	81
Thymus and spleen	Mdmx^-/-	Trp53^ER/-	Apoptosis	85
Testis	Mdm2^-/-	Trp53^ER/-	Arrest	81
Testis	Mdmx^-/-	Trp53^ER/-	Not reported	85
Lung, kidney and liver	Mdm2^-/-	Trp53^ER/-	No effect	81
Lung, kidney and liver	Mdmx^-/-	Trp53^ER/-	No effect	85

CNS, central nervous system; Epor, erythropoietin receptor; FM, floxed Mdm2 allele; FX, floxed Mdmx allele; GFP, green fluorescent protein; Myhc, myosin heavy chain; Sm22, smooth muscle protein 22 (also known as transgelin); SVZ, subventricular zone.

Knockout of MDM2 or MDMX is embryonic lethal, and therefore either MDM knockout or p53 expression must be rendered conditional. This is usually achieved using Cre-mediated recombination. Note that the Trp53^LSL and Trp53^ER systems are to some extent ‘leaky’. Thus, adult animals can only be obtained by reducing Trp53 to hemizygosity.

^‡

Phenotype is for the adult tissue, except where the knockout was embryonic lethal.