1
|
Veríssimo A, Castro LFC, Muñoz-Mérida A, Almeida T, Gaigher A, Neves F, Flajnik MF, Ohta Y. An Ancestral Major Histocompatibility Complex Organization in Cartilaginous Fish: Reconstructing MHC Origin and Evolution. Mol Biol Evol 2023; 40:msad262. [PMID: 38059517 PMCID: PMC10751288 DOI: 10.1093/molbev/msad262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/06/2023] [Accepted: 11/27/2023] [Indexed: 12/08/2023] Open
Abstract
Cartilaginous fish (sharks, rays, and chimeras) comprise the oldest living jawed vertebrates with a mammalian-like adaptive immune system based on immunoglobulins (Ig), T-cell receptors (TCRs), and the major histocompatibility complex (MHC). Here, we show that the cartilaginous fish "adaptive MHC" is highly regimented and compact, containing (i) a classical MHC class Ia (MHC-Ia) region containing antigen processing (antigen peptide transporters and immunoproteasome) and presenting (MHC-Ia) genes, (ii) an MHC class II (MHC-II) region (with alpha and beta genes) with linkage to beta-2-microglobulin (β2m) and bromodomain-containing 2, (iii) nonclassical MHC class Ib (MHC-Ib) regions with 450 million-year-old lineages, and (iv) a complement C4 associated with the MHC-Ia region. No MHC-Ib genes were found outside of the elasmobranch MHC. Our data suggest that both MHC-I and MHC-II genes arose after the second round of whole-genome duplication (2R) on a human chromosome (huchr) 6 precursor. Further analysis of MHC paralogous regions across early branching taxa from all jawed vertebrate lineages revealed that Ig/TCR genes likely arose on a precursor of the huchr9/12/14 MHC paralog. The β2m gene is linked to the Ig/TCR genes in some vertebrates suggesting that it was present at 1R, perhaps as the donor of C1 domain to the primordial MHC gene. In sum, extant cartilaginous fish exhibit a conserved and prototypical MHC genomic organization with features found in various vertebrates, reflecting the ancestral arrangement for the jawed vertebrates.
Collapse
Affiliation(s)
- Ana Veríssimo
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão 4485-661, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão 4485-661, Portugal
| | - L Filipe C Castro
- Department of Biology, Faculty of Sciences, University of Porto, Porto 4169-007, Portugal
- CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Matosinhos, Portugal
| | - Antonio Muñoz-Mérida
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão 4485-661, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão 4485-661, Portugal
| | - Tereza Almeida
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão 4485-661, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão 4485-661, Portugal
| | - Arnaud Gaigher
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão 4485-661, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão 4485-661, Portugal
- Research Group for Evolutionary Immunogenomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
- Research Unit for Evolutionary Immunogenomics, Department of Biology, University of Hamburg, Hamburg, Germany
| | - Fabiana Neves
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão 4485-661, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão 4485-661, Portugal
| | - Martin F Flajnik
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Yuko Ohta
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| |
Collapse
|