identification of two new hla-g alleles, g*01:01:03:03 and g*01:01:21, in brazilian individuals

Identification of two new HLA-G alleles, G*01:01:03:03 and G*01:01:21, in Brazilian individualsE. C. Castelli1, R. S. de Albuquerque2, L. C. Veiga-Castelli2, L. P. Felıcio1, K. Beachemin3, M. C. Faucher3, P. Moreau4, E. A. Donadi2 & M. Roger3,5

1 Institute of Biological Sciences, Federal University of Goias, Goiania, Brazil2 Division of Clinical Immunology, Department of Medicine, School of Medicine of Ribeirao Preto, University of Sao Paulo, Sao Paulo, Brazil3 Laboratoire d’Immunogenetique, Centre de Recherche du Centre Hospitalier de l’Universite de Montreal (CRCHUM), Montreal, Canada4 Commissariat a l’Energie Atomique et aux Energies Alternatives, Universite Paris VII/DSV/I2BM/Service de Recherches en Hemato-Immunologie, Institut Universitaired’Hematologie, Hopital Saint-Louis, Paris, France5 Departement de Microbiologie et Immunologie, Universite de Montreal, Montreal, Canada

Key words: Brazil; human leukocyte antigen-G; polymorphism; sequence-based typing

Here we report two new non-classical class I HLA-Galleles found in the Brazilian population.

The HLA-G is a non-classical class I gene that encodes amolecule with immunomodulatory properties. The HLA-Gmolecule is primarily expressed on the maternal–fetal inter-face, protecting the fetus from the maternal immune system.The HLA-G molecule has a restricted tissue distribution, beenexpressed on cornea, thymus, nail matrix, pancreas and insome cases of cancer and autoimmune diseases (1, 2). TheHLA-G gene presents a very low polymorphism comparedwith the classical class I genes. Currently there are 47 offi-cial alleles encompassing 15 different full-length proteins andtwo null alleles in the IMGT/HLA Database version 3.7.0(International Immunogenetics Database/HLA), but only fivealleles are frequently found in worldwide population, includ-ing Brazilians (1).

Brazilians represent one of the most heterogeneous popu-lations in the world as a result of five centuries of interethniccrosses of people from three continents: the European coloniz-ers, mainly represented by the Portuguese, the African slavesand the autochthonous Amerindians. In this matter, a greatHLA-G variability would be expected in such population. Infact, in a study investigating the entire variability and the link-age disequilibrium among the variation sites of the 5′ upstreamregulatory, coding and 3′ untranslated region of the HLA-G

gene (2), we found two new HLA-G alleles in the Brazilianpopulation. These two new variants were officially assigned by

the WHO Nomenclature Committee as HLA-G*01:01:03:03and HLA-G*01:01:21.

The novel allele HLA-G*01:01:03:03 was found in twonon-related bone marrow donors (a man and a woman) fromRibeirao Preto, North of Sao Paulo State, Brazil. This newvariant is probably derived from the allele G*01:01:03:01by three mutations: a C→A transversion at intron 3 (posi-tion +1128 according to IMGT/HLA), a C→T transition atintron 5 (position +2462) and an A→G transition at the 3′

untranslated region – 3′UTR (position +2519). Since all thenew mutations are intronic or in the 3′UTR, this allele prob-ably generates the most common full-length HLA-G pro-tein, i.e. G*01:01 (1) and its accession number is JQ013009.The second new allele, HLA-G*01:01:21, presents a newsynonymous mutation and was found in one woman fromthe same cohort. This new allele is probably derived fromG*01:01:01:05 by a synonymous mutation at exon 2, posi-tion +237 according to IMGT/HLA, last base of codon 12,GTG to GTC (valine → valine). This new allele is alsoassociated with G*01:01 protein and its accession number isJQ013008.

The DNA sample was obtained from peripheral blood usingthe salting-out method. The two new variants were identifiedby direct sequencing of PCR products using the BigDye®

Terminator v.3.1 Cycle Sequencing kit and an ABI 3100Genetic Analyzer (Applied Biosystem, New York, NY). Afragment of approximately 5 Kb encompassing the promoterto the 3′UTR region using a high-fidelity DNA polymerasewas generated, cloned into an appropriate vector (TOPOXL PCR Cloning Kit; Life Technologies) and completelysequenced (2).

70 © 2012 John Wiley & Sons A/STissue Antigens, 2012, 80, 65–71

In conclusion, here we presented two new rare HLA-Galleles, HLA-G*01:01:03:03 and HLA-G*01:01:21, that werefound in the Brazilian population.

CorrespondenceDr Erick C. CastelliDepartamento de Biologia GeralInstituto de Ciencias BiologicasUniversidade Federal de Goias. UFG – Campus Samambaia(Campus II) – ICB IIsala 215GoianiaGoias, CEP 74001-970BrazilTel: 55 62 3521 1725e-mail: erick.castelli@gmail.com

doi: 10.1111/j.1399-0039.2012.01869.x

Acknowledgments

This study was supported by the Brazilian National Research Coun-cil (CNPq/Brazil – Grants 475670/2007-8 and 558476/2008-0) andthe binational collaborative research program CAPES-COFECUB

(project # 653/09). L. C. V. C is supported by a postdoctoral fel-lowship (150329/2011-3) from CNPq/Brazil. M. R. is recipient ofResearch Scholar Award from the Fonds de la Recherche en Santedu Quebec.

Conflict of interest

The authors have declared no conflicting interests.

References

1. Donadi EA, Castelli EC, Arnaiz-Villena A, Roger M, Rey D,Moreau P. Implications of the polymorphism of HLA-G on itsfunction, regulation, evolution and disease association. Cell Mol LifeSci 2011: 68: 369–95.

2. Castelli EC, Mendes-Junior CT, Veiga-Castelli LC, Roger M,Moreau P, Donadi EA. A comprehensive study of polymorphic sitesalong the HLA-G gene: implication for gene regulation andevolution. Mol Biol Evol 2011: 28: 3069–86.

© 2012 John Wiley & Sons A/S 71Tissue Antigens, 2012, 80, 65–71