Mutation analysis of left-right axis determining genes in NOD and ICR, strains susceptible to maternal diabetes.
BACKGROUND
Genetic background of the fetus contributes to the pathogenesis of congenital malformation after teratogen exposure. Such contribution is illustrated in left-right axis malformations observed in the F1 offspring of nonobese diabetic (NOD) mouse dams and sires from different strains. When sires of the NOD, ICR, or C57BL/6J were mated with NOD dams, incidence varied depending on the fetal genotype, with 65% in NOD x NOD, 24% in NOD x ICR, and 7% in NOD x C57BL/6J.


METHODS
As a first step in elucidating the molecular basis of the interstrain differences in susceptibility to situs defects, we compared genomic sequences of six genes HNF3beta, Acvr2b, Nodal, ZIC3, Lefty1, and Smad2, which are involved in the normal development of left-right axis among NOD, ICR, and C57BL/6J strains.


RESULTS
The outbred strain ICR had 1) a 0.2-kb insertion in the putative promoter region of the isoform E of HNF3beta together with a G to A change that could create a potential splice acceptor in the exon 3 of HNF3beta (gene frequency P = 0.36), 2) five single base substitutions within the 5' controlling element and a proline to serine substitution (P2S) of Lefty1 (P = 0.77), and 3) a tyrosine to histidine substitution within the prodomain of Nodal (P = 0.48). The inbred strain NOD had the same G to A change as ICR and a three-base deletion in the putative promoter of isoform E of HNF3beta.


CONCLUSIONS
We suggest that sequence variations in HNF3beta, Lefty1, and Nodal might account, in part, for the interstrain differences in susceptibility to situs abnormalities among the offspring of diabetic dams.
Department of Pediatrics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Maeyama
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Kosaki
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Yoshihashi
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Casey
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Kosaki
D000818:Animals; D004252:DNA Mutational Analysis; D017931:DNA Primers / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000235:genetics; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics*; D016640:Diabetes, Gestational; D005260:Female; D014644:Genetic Variation; D051542:Hepatocyte Nuclear Factor 3-beta; D018398:Homeodomain Proteins / Q000235:genetics; D055458:Left-Right Determination Factors; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D016688:Mice, Inbred NOD; D005810:Multigene Family / Q000235:genetics*; D009154:Mutation; D055457:Nodal Protein; D009687:Nuclear Proteins / Q000235:genetics; D011247:Pregnancy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012857:Situs Inversus / Q000235:genetics*; D051899:Smad2 Protein; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D016212:Transforming Growth Factor beta / Q000235:genetics
D017931:DNA Primers; D004268:DNA-Binding Proteins; C496503:Foxa2 protein, mouse; D018398:Homeodomain Proteins; D055458:Left-Right Determination Factors; D055457:Nodal Protein; C526008:Nodal protein, mouse; D009687:Nuclear Proteins; D051899:Smad2 Protein; C497783:Smad2 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; C491594:Zic3 protein, mouse; D051542:Hepatocyte Nuclear Factor 3-beta