KIR2DL4 genetic diversity in a Brazilian population sample: implications for transcription regulation and protein diversity in samples with different ancestry backgrounds

• Published in: bioRxiv
• Main Authors: Weiss, Emiliana, Andrade, Heloisa S, Juliana Rodrigues Lara, Souza, Andreia S, Paz, Michelle A, Lima, Thálitta H A, Porto, Iane O P, Nayane Dos S B Silva, Camila F Bannwart Castro, Grotto, Rejane M T, Donadi, Eduardo A, Mendes-Junior, Celso T, Castelli, Erick C
• Format: Paper
• Language: English
• Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 21.11.2020
• Subjects: Exons; Gene families; Gene frequency; Gene mapping; Gene regulation; Genetic diversity; Genotypes; Genotyping; Haplotypes; Histocompatibility antigen HLA; Introns; Killer cell immunoglobulin-like receptors; KIR2DL4 protein; Linkage disequilibrium; Natural killer cells; Potassium channels (inwardly-rectifying); Transcription; Brazil
• DOI: 10.1101/2020.11.20.391649

Abstract KIR2DL4 is an important immune modulator expressed in Natural Killer cells, being HLA-G its main ligand. We characterize KIR2DL4 gene diversity considering the promoter, all exons, and all introns, in a highly admixed Brazilian population sample using massively parallel sequencing. We also introduce a molecular method to amplify and sequence the complete KIR2DL4 gene. To avoid mapping bias and genotype errors commonly observed in gene families, we have developed a bioinformatic pipeline designed to minimize mapping, genotyping, and haplotyping errors. We have applied this method to survey the variability of 220 samples from the State of São Paulo, southeastern Brazil. We have also compared the KIR2DL4 genetic diversity in Brazilian samples with the previously reported by the 1000Genomes consortium. KIR2DL4 presents high linkage disequilibrium throughout the gene, with coding sequences associated with specific promoters. There were few, but divergent, promoter haplotypes. We have also detected many new KIR2DL4 sequences, all with nucleotide exchanges in introns and encoding previously described proteins. Exons 3 and 4, which encode the external domains, were the most variable ones. The ancestry background influences KIR2DL4 allele frequencies and must be considered for association studies regarding KIR2DL4. Competing Interest Statement The authors have declared no competing interest. Footnotes * ↵* Contact: Erick C. Castelli, Departamento de Patologia, Faculdade de Medicina de Botucatu, Unesp – Botucatu, SP. CEP: 18618970, Brazil, Phone: +55 14 3880-1696, E-mail address: erick.castelli{at}unesp.br.