Related Experiment Video
Updated: Aug 8, 2026
Parasite Induced Genetically Driven Autoimmune Chagas Heart Disease in the Chicken Model
Published on: July 29, 2012
Identification of the Tapasin gene in the chicken major histocompatibility complex
B Frangoulis1, I Park, F Guillemot
1Unité de Génétique Moléculaire et de Biologie du Développement (CNRS UPR 420), 19 rue Guy Moquet, BP 8, F-94801 Villejuif Cedex, France. frangoul@infobiogen.fr
Insights
Researchers identified the chicken Tapasin gene within the Major Histocompatibility Complex (Mhc), crucial for assembling Mhc class I molecules. This finding reveals structural differences and potential alternative functions of the Tapasin protein in chickens.
Area of Science:
- Immunogenetics
- Molecular Biology
- Comparative Genomics
Background:
- Tapasin is essential for Major Histocompatibility Complex (Mhc) class I assembly in the endoplasmic reticulum.
- It facilitates the interaction between class I-beta2-microglobulin dimers and the TAP transporter.
- Understanding Tapasin's role is key to comprehending immune system function and diversity.
Purpose of the Study:
- To identify and characterize the Tapasin gene in the chicken Mhc (B complex).
- To compare the structure of chicken Tapasin with its human counterpart.
- To investigate potential alternative splicing of the chicken Tapasin gene.
Main Methods:
- Gene identification and sequencing within the chicken Mhc B complex.
- Comparative analysis of gene structure (exons, introns) with human Tapasin.
- Isolation and analysis of complementary DNAs (cDNAs) to identify alternative splicing.
Main Results:
- The chicken Tapasin gene was located at the centromeric end of the Mhc B complex.
- Chicken Tapasin comprises 8 exons with significantly smaller introns than human Tapasin.
- Two distinct cDNAs were identified, suggesting alternative splicing, with one lacking an immunoglobulin-like domain.
Conclusions:
- Chicken Tapasin is a transmembrane protein with an endoplasmic reticulum retention signal.
- Exons III, IV, and V encode immunoglobulin superfamily-related domains, a novel finding for human Tapasin domain IV.
- Alternative splicing may lead to functionally distinct Tapasin protein variants in chickens.
Abstract:
The Tapasin molecule plays a role in the assembly of major histocompatibility complex (Mhc) class I molecules in the endoplasmic reticulum, by mediating the interaction of class I-beta2-microglobulin dimers with TAP. We report here the identification of the Tapasin gene in the chicken Mhc (B complex). This gene is located at the centromeric end of the complex, between the class II B-LBI and B-LBII genes. Like its human counterpart it comprises 8 exons, but features a significantly reduced intron size as compared to the human gene. Chicken Tapasin codes for a transmembrane protein with a probable endoplasmic reticulum retention signal. Exons IV and V, and possibly exon III, code for separate domains that are related to the immunoglobulin (Ig) superfamily (this relationship was so far unrecognized for human Tapasin domain IV which has lost its two cysteines). Two different cDNAs corresponding to the Tapasin gene were isolated, possibly related to alternative splicing events; the Ig-like domain encoded by exon IV is missing in one of the cDNAs, suggesting either that this domain is not necessary for the protein to perform its function, or that the two alternatively spliced cDNAs are translated into two functionally different forms of the protein.
