Novel strategy using F1-congenic mice for validation of QTLs: studies at the proximal chromosome 10 atherosclerosis susceptibility locus.

We have previously identified a quantitative trait locus (QTL) for atherosclerosis susceptibility on proximal chromosome 10 (Chr10) (Ath11) in independent crosses of FVB and C57BL/6 (B6) mice on the apolipoprotein E (ApoE-/-) and LDL receptor (LDLR-/-) deficient backgrounds. The aims of the current study were to (1) test a novel strategy for validating QTLs using interval-specific congenic strains that were heterozygous (F1) across the genome, (2) validate the Chr10 QTL, and (3) to assess whether the phenotype is transferable by bone marrow transplantation. We generated Chr10 (0 to 21 cM) interval-specific mice on the F1.ApoE-/- background by crossing congenic FVB.ApoE-/-Chr10(B6/FVB) with B6.ApoE-/-, and B6.ApoE-/-Chr10(B6/FVB) with FVB.ApoE-/- mice. Lesion size was significantly larger in the resultant F1.ApoE-/-Chr10(FVB/FVB) mice compared to F1.ApoE-/-Chr10(B6/FVB) and F1.ApoE-/-Chr10(B6/B6) mice, validating the Chr10 QTL. The effect of the congenic interval was more robust on the F1.ApoE-/- than on the FVB.ApoE-/- and B6.ApoE-/- backgrounds. Bone marrow transplantation in congenic mice showed that the effect of the proximal Chr10 interval was not transferable by bone marrow-derived cells. A novel strategy of congenic strains on an F1 background proved useful to validate an atherosclerosis susceptibility QTL on mouse proximal Chr10.