RESUMO
We recently mapped Idd4 to a 5.2 cM interval on chromosome 11 with two subloci, Idd4.1 and Idd4.2, in nonobese diabetic (NOD) mice. Based on the localization of platelet-activating factor acetylhydrolase Ib1 (PAF-AHIb1) and the decreased activity of PAF-AH in type 1 diabetes (T1D) patients, we hypothesized that PAF-AHIb1 in Idd4.1 is a candidate gene. The PAF-AHIb1 gene in NOD mice was cloned and sequenced, and its expression and function were studied. No polymorphisms were detected in PAF-AHIb1 cDNA between NOD and B6 mice. The expression of PAF-AH Ib1 at the mRNA and protein levels was found to be similar in different tissues between NOD and B6 mice. PAF-AH activity does not differ in the pancreatic islets or spleen between NOD and B6 mice. Our findings suggest that PAF-AH Ib1 may not be a diabetes-susceptibility gene in the Idd4.1 sublocus.