The MHC Class II-Associated Chicken Invariant Chain Shares Functional Properties with Its Mammalian Homologs

• Published in: Experimental cell research Vol. 259; no. 2; pp. 360 - 369
• Main Authors: Bremnes, Bjørn, Rode, Marit, Gedde-Dahl, Merete, Nordeng, Tommy W., Jacobsen, Jorunn, Ness, Scott A., Bakke, Oddmund
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-09-2000
• Subjects: Animals; Antigens, Differentiation, B-Lymphocyte - analysis; Antigens, Differentiation, B-Lymphocyte - genetics; Antigens, Differentiation, B-Lymphocyte - immunology; Cell Membrane - chemistry; Cell Membrane - immunology; chicken; Chickens; Cloning, Molecular; DNA, Complementary; endocytosis; Endocytosis - immunology; Endosomes - chemistry; Endosomes - immunology; Gene Expression - immunology; Histocompatibility Antigens Class II - analysis; Histocompatibility Antigens Class II - genetics; Histocompatibility Antigens Class II - immunology; Humans; invariant chain; Leucine; leucine-based signal; Mammals; MHC class II; Molecular Sequence Data; Protein Sorting Signals - genetics; Protein Sorting Signals - immunology; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - immunology; Sequence Homology, Amino Acid; Signal Transduction - immunology; Transfection; leucine-based signal; endocytosis; chicken; MHC class II; invariant chain
• ISSN: 0014-4827; 1090-2422
• DOI: 10.1006/excr.2000.4985

The nucleotide sequence of chicken invariant chain (Ii) was determined, and the amino acid sequence similarity with human Ii is 61%. Certain regions important for the biological function of human Ii are highly conserved between chicken and mammals. The cytoplasmic tail of chicken Ii fused to the plasma membrane reporter molecule neuraminidase relocated the protein to endosomes. Moreover, like the mammalian orthologs, the cytoplasmic tail was found to contain two independent leucine-based endosomal sorting signals. Chicken Ii was found to interact with human Ii and crosslinking studies also indicate that chicken Ii assembles as a trimer. The chicken Ii can furthermore bind the human MHC class II (HLA-DR1). Many of the functional properties between the chicken Ii and its mammalian orthologs are thus maintained in spite of their sequence differences.