Fig 4. Effects of genetic backgrounds on the ectopic Stab2 gene expression in the hearts.

Hearts of 3 weeks old mice were isolated and the Stab2 mRNA levels were determined by RT-PCR. (A) Expression relative to the hearts of DBA/2J mice was expressed as fold difference in log2 scale to emphasize the genetic background effects. Left panel: F1 mice were generated from crosses of 129S6 females and DBA/2J males (129,DBA-F1) or DBA/2J females and 129S6 males (DBA,129-F1). Note F1 mice all carry one copy of DBA/2J genome and one copy of 129S6 genome. Stab2DD is a congenic strain in which the Stab2^DBA allele was transferred onto a 129S6 genetic background by more than 6 generations of serial backcrosses and are homozygous for Stab2^DBA. Right panel: F1 mice were generated from crosses of C57BL/6J females and DBA/2J males (B6,DBA-F1) or DBA/2J females and C57BL/6J males (DBA,B6-F1). Green diamonds illustrates a group mean (middle horizontal bars) and confidence intervals (height of the diamonds). (B) Relative expression levels (%DBA) in the hearts of individual mice heterozygous for the Stab2^DBA allele derived from 129,DBA-F1 females backcrossed to 129S6 males (DS at Stab2) and from B6,DBA-F1 females backcrossed to C57BL/6J males (DB at Stab2). All mice presented have at least one copy of 129S6 (or C57BL/6J) at other parts of genome. (C) Expression levels (%DBA) in the hearts of individual mice heterozygous for Stab2^DBA allele derived from 129,DBA-F1 females or B6,DBA-F1 females backcrossed to DBA/2J males. Only those heterozygous for Stab2^DBA are presented. All mice have at least one copy of DBA genome but randomly carry segments of DBA/2J genome. Genotypes of Stab2 at Chr10 and a Chr13:67 Mb marker were determined. DSDD and DBDD indicate heterozygotes for Stab2^DBA and homozygous for Chr13:66 Mb of DBA/2J. DSDS and DBDB indicate heterozygotes at both loci.