Physiol. Genomics 38: 89-97, 2009.
First published April 7, 2009; doi:10.1152/physiolgenomics.00015.2009

1094-8341/09 $8.00
Received 21 January 2009;
accepted in final form 6 April 2009.
Physiological Genomics 38:89-97 (2009)
1094-8341/09 $8.00 © 2009 American Physiological Society
Genetic dissection reveals diabetes loci proximal to the gimap5 lymphopenia gene
J. M. Fuller
1,2,
M. Bogdani
3,
T. D. Tupling
2,
R. A. Jensen
2,
R. Pefley
2,
S. Manavi
2,
L. Cort
4,
E. P. Blankenhorn
4,
J. P. Mordes
5,
Å. Lernmark
1,2 and
A. E. Kwitek
6
1 Department of Clinical Sciences, Lund University, and Clinical Research Center, Malmö, Sweden
2 Department of Medicine, University of Washington
3 Pacific Northwest Research Institute, Seattle, Washington
4 Department of Microbiology and Immunology, Center for Immunogenetics and Inflammatory Diseases, Drexel University College of Medicine, Philadelphia, Pennsylvania
5 Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
6 Department of Internal Medicine, Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa
Congenic DRF.f/f rats are protected from type 1 diabetes (T1D) by 34 Mb of F344 DNA introgressed proximal to the gimap5 lymphopenia gene. To dissect the genetic factor(s) that confer protection from T1D in the DRF.f/f rat line, DRF.f/f rats were crossed to inbred BBDR or DR.lyp/lyp rats to generate congenic sublines that were genotyped and monitored for T1D, and positional candidate genes were sequenced. All (100%) DR.lyp/lyp rats developed T1D by 83 days of age. Reduction of the DRF.f/f F344 DNA fragment by 26 Mb (42.52–68.51 Mb) retained complete T1D protection. Further dissection revealed that a 2 Mb interval of F344 DNA (67.41–70.17 Mb) (region 1) resulted in 47% protection and significantly delayed onset (P < 0.001 compared with DR.lyp/lyp). Retaining <1 Mb of F344 DNA at the distal end (76.49–76.83 Mb) (region 2) resulted in 28% protection and also delayed onset (P < 0.001 compared with DR.lyp/lyp). Comparative analysis of diabetes frequency in the DRF.f/f congenic sublines further refined the RNO4 region 1 interval to
670 kb and region 2 to the 340 kb proximal to gimap5. All congenic DRF.f/f sublines were prone to low-grade pancreatic mononuclear cell infiltration around ducts and vessels, but <20% of islets in nondiabetic rats showed islet infiltration. Coding sequence analysis revealed TCR Vβ 8E, 12, and 13 as candidate genes in region 1 and znf467 and atp6v0e2 as candidate genes in region 2. Our results show that spontaneous T1D is controlled by at least two genetic loci 7 Mb apart on rat chromosome 4.
type 1 diabetes; BB rat; T cell receptor; autoimmune
Copyright © 2009 by the American Physiological Society.