The major histocompatibility complex (MHC) is a highly polymorphic region of the genome essential to immune responses and animal health. In galliforms, the MHC is divided into 2 genetically unlinked regions (MHC-B and MHC-Y). Many MHC-B genes are involved in adaptive or innate immunity, yet others have nonimmune or unknown functions. The sequenced MHC-B region of the turkey (Meleagris gallopavo) contains 40 genes, the majority of which are predicted transcripts based on comparison with the chicken or quail, without direct evidence for expression. This study was designed to test for the presence of MHC-B gene transcripts in a panel of immune and nonimmune system tissues from domestic turkeys. This analysis provides the first locus-wide examination of MHC-B gene expression in any avian species. Most MHC-B genes were broadly expressed across tissues. Expression of all predicted genes was verified by reverse-transcription PCR, including B-butyrophilin 2 (BTN2), a predicted gene with no previous evidence for expression in any species. Previously undescribed splice variants were also detected and sequenced from 3 genes. Characterization of MHC-B expression patterns helps elucidate unknown gene functions and potential gene coregulation. Determining turkey MHC-B expression profiles increases our overall understanding of the avian MHC and provides a necessary resource for future research on the immunological response of these genes.
Bibliographical noteFunding Information:
The authors thank Sally Noll (UMN, St. Paul, MN) and the Willmar Poultry Co. (Willmar, MN) for providing access to domestic turkey tissue and blood samples. The authors thank Miranda Bauer (UMN, St. Paul, MN) for assistance with sample collection and RNA isolation from some OSU and Willmar samples and Kelly Sporer (MSU, East Lansing, MI) for RNA ex- traction and DNase treatment of MSU muscle samples. This research was funded by USDA-Cooperative State Research, Education, and Extension Service National Research Initiative Grants #2005-01326 and 2009-35205-05302.
- Gene expression
- Major histocompatibility complex