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. 2019 Oct 3;10:2237. doi: 10.3389/fimmu.2019.02237

Figure 4.

Figure 4

FCGR3 exons. Exons are shown by boxes. Exon names are below and followed by the number of coding base pairs in that exon. S1, S2, signal peptides; EC1, EC2, extracellular domains; TM: transmembrane domain. Several SNPs are indicated in the figure, all are indicated by their amino-acid position in the full protein, followed by the amino acid position excluding signal peptides between brackets for some of the SNP which are commonly known by that position. Sequences for FCGR3A and FCGR3B are very similar, but four non-synonymous differences in the coding sequence exist, most notably the stop codon at p.234 in FCGR3B as indicated in the figure, which truncates the transmembrane domain of this receptor. Other amino acid differences between FCGR3A and FCGR3B include p.147 (Gly in FCGR3A, Asp in FCGR3B), p.158 (Tyr in FCGR3A, His in FCGR3B) and p.203 (Phe in FCGR3A, Ser in FCGR3B) (41). A set of 6 SNPs in exon3 of FCGR3B form three rather well-defined haplotypes, the FCGR3B-NA1, -NA2 and -SH. FCGR3A is identical to NA1 at some sites, but to NA2 at others (41).