Identification of a chimeric BTNL8*3 product. (A) In LCLs carrying one or two copies of the BTNL8_BTNL3-del allele, a fusion BTNL8*3 mRNA product could be detected by RT-PCR. (B) Allelic expression differences are shown in individual tissues. In tissues heterozygous for the BTNL8*3 allele, the non-deleted BTNL8 allele was expressed threefold higher than the BTNL8*3 allele (all tissues combined). (C) Representative western blot analysis revealed a novel protein in LCL cells expressing the deleted allele. The band intensities were normalized to tubulin expression. (D) The putative protein resulting from the BTNL8*3 deletion CNV would contain the extracellular IgV-like and IgC-like domains and the TM domain of BTNL8 and the cytoplasmic B30.2 domain of BTNL3.