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Multiple expressed MHC class II loci in salmonids; details of one non-classical region in Atlantic salmon (Salmo salar)

BACKGROUND: In teleosts, the Major Histocompatibility Complex (MHC) class I and class II molecules reside on different linkage groups as opposed to tetrapods and shark, where the class I and class II genes reside in one genomic region. Several teleost MHC class I regions have been sequenced and show...

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Autores principales: Harstad, Håvard, Lukacs, Morten F, Bakke, Hege G, Grimholt, Unni
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2386828/
https://www.ncbi.nlm.nih.gov/pubmed/18439319
http://dx.doi.org/10.1186/1471-2164-9-193
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author Harstad, Håvard
Lukacs, Morten F
Bakke, Hege G
Grimholt, Unni
author_facet Harstad, Håvard
Lukacs, Morten F
Bakke, Hege G
Grimholt, Unni
author_sort Harstad, Håvard
collection PubMed
description BACKGROUND: In teleosts, the Major Histocompatibility Complex (MHC) class I and class II molecules reside on different linkage groups as opposed to tetrapods and shark, where the class I and class II genes reside in one genomic region. Several teleost MHC class I regions have been sequenced and show varying number of class I genes. Salmonids have one major expressed MHC class I locus (UBA) in addition to varying numbers of non-classical genes. Two other more distant lineages are also identifyed denoted L and ZE. For class II, only one major expressed class II alpha (DAA) and beta (DAB) gene has been identified in salmonids so far. RESULTS: We sequenced a genomic region of 211 kb encompassing divergent MHC class II alpha (Sasa-DBA) and beta (Sasa-DBB) genes in addition to NRGN, TIPRL, TBCEL and TECTA. The region was not linked to the classical class II genes and had some synteny to genomic regions from other teleosts. Two additional divergent and expressed class II sequences denoted DCA and DDA were also identified in both salmon and trout. Expression patterns and lack of polymorphism make these genes non-classical class II analogues. Sasa-DBB, Sasa-DCA and Sasa-DDA had highest expression levels in liver, hindgut and spleen respectively, suggestive of distinctive functions in these tissues. Phylogenetic studies revealed more yet undescribed divergent expressed MHC class II molecules also in other teleosts. CONCLUSION: We have characterised one genomic region containing expressed non-classical MHC class II genes in addition to four other genes not involved in immune function. Salmonids contain at least two expressed MHC class II beta genes and four expressed MHC class II alpha genes with properties suggestive of new functions for MHC class II in vertebrates. Collectively, our data suggest that the class II is worthy of more elaborate studies also in other teleost species.
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spelling pubmed-23868282008-05-17 Multiple expressed MHC class II loci in salmonids; details of one non-classical region in Atlantic salmon (Salmo salar) Harstad, Håvard Lukacs, Morten F Bakke, Hege G Grimholt, Unni BMC Genomics Research Article BACKGROUND: In teleosts, the Major Histocompatibility Complex (MHC) class I and class II molecules reside on different linkage groups as opposed to tetrapods and shark, where the class I and class II genes reside in one genomic region. Several teleost MHC class I regions have been sequenced and show varying number of class I genes. Salmonids have one major expressed MHC class I locus (UBA) in addition to varying numbers of non-classical genes. Two other more distant lineages are also identifyed denoted L and ZE. For class II, only one major expressed class II alpha (DAA) and beta (DAB) gene has been identified in salmonids so far. RESULTS: We sequenced a genomic region of 211 kb encompassing divergent MHC class II alpha (Sasa-DBA) and beta (Sasa-DBB) genes in addition to NRGN, TIPRL, TBCEL and TECTA. The region was not linked to the classical class II genes and had some synteny to genomic regions from other teleosts. Two additional divergent and expressed class II sequences denoted DCA and DDA were also identified in both salmon and trout. Expression patterns and lack of polymorphism make these genes non-classical class II analogues. Sasa-DBB, Sasa-DCA and Sasa-DDA had highest expression levels in liver, hindgut and spleen respectively, suggestive of distinctive functions in these tissues. Phylogenetic studies revealed more yet undescribed divergent expressed MHC class II molecules also in other teleosts. CONCLUSION: We have characterised one genomic region containing expressed non-classical MHC class II genes in addition to four other genes not involved in immune function. Salmonids contain at least two expressed MHC class II beta genes and four expressed MHC class II alpha genes with properties suggestive of new functions for MHC class II in vertebrates. Collectively, our data suggest that the class II is worthy of more elaborate studies also in other teleost species. BioMed Central 2008-04-28 /pmc/articles/PMC2386828/ /pubmed/18439319 http://dx.doi.org/10.1186/1471-2164-9-193 Text en Copyright © 2008 Harstad et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Harstad, Håvard
Lukacs, Morten F
Bakke, Hege G
Grimholt, Unni
Multiple expressed MHC class II loci in salmonids; details of one non-classical region in Atlantic salmon (Salmo salar)
title Multiple expressed MHC class II loci in salmonids; details of one non-classical region in Atlantic salmon (Salmo salar)
title_full Multiple expressed MHC class II loci in salmonids; details of one non-classical region in Atlantic salmon (Salmo salar)
title_fullStr Multiple expressed MHC class II loci in salmonids; details of one non-classical region in Atlantic salmon (Salmo salar)
title_full_unstemmed Multiple expressed MHC class II loci in salmonids; details of one non-classical region in Atlantic salmon (Salmo salar)
title_short Multiple expressed MHC class II loci in salmonids; details of one non-classical region in Atlantic salmon (Salmo salar)
title_sort multiple expressed mhc class ii loci in salmonids; details of one non-classical region in atlantic salmon (salmo salar)
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2386828/
https://www.ncbi.nlm.nih.gov/pubmed/18439319
http://dx.doi.org/10.1186/1471-2164-9-193
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