A Deadly Cargo: Gene Repertoire of Cytotoxic Effector Proteins in the Camelidae

Abstract

Cytotoxic T cells and natural killer cells can kill target cells based on their expression and release of perforin, granulysin, and granzymes. Genes encoding these molecules have been only poorly annotated in camelids. Based on bioinformatic analyses of genomic resources, sequences corresponding to perforin, granulysin, and granzymes were identified in genomes of camelids and related ungulate species, and annotation of the corresponding genes was performed. A phylogenetic tree was constructed to study evolutionary relationships between the species analyzed. Re-sequencing of all genes in a panel of 10 dromedaries and 10 domestic Bactrian camels allowed analyzing their individual genetic polymorphisms. The data showed that all extant Old World camelids possess functional genes for two pore-forming proteins (PRF1, GNLY) and six granzymes (GZMA, GZMB, GZMH, GZMK, GZMM, and GZMO). All these genes were represented as single copies in the genome except the GZMH gene exhibiting interspecific differences in the number of loci. High protein sequence similarities with other camelid and ungulate species were observed for GZMK and GZMM. The protein variability in dromedaries and Bactrian camels was rather low, except for GNLY and chymotrypsin-like granzymes (GZMB, GZMH).

The deadly face of felid killer cells: The cytotoxic proteins and their genes

“…For example, the amino acid sequences of mouse and human GZMB are about 70% identical, while the similarities between GZMs of other subfamilies are much lower, even with the same species 2 . We have observed this situation also in camelids 43 and the same differentiation between GZMs subfamilies can be observed for the annotated felid genes.…”

“…We have shown previously that camels possess one or two variants for trypsin-like granzymes (GZMA and GZMK), while their chymotrypsin-like granzymes were more diverse with three to five variants of GZMB and two to four variants of GZMH. 43 The low level of polymorphism of GZM genes in Felidae species (Table 3) is similar to the findings in dog genes. Exceptions to this finding include GZMK in Prionailurus bengalensis and Panthera leo with F I G U R E 3 Phylogenetic tree of felid granzyme GZMB based on merged sets of coding sequence haplotypes.…”

“…A comparison of five reference genomes of the domestic dog showed only one variant for GZMB and GZMK and two variants for GZMA and GZMH (Table 2). We have shown previously that camels possess one or two variants for trypsin‐like granzymes (GZMA and GZMK), while their chymotrypsin‐like granzymes were more diverse with three to five variants of GZMB and two to four variants of GZMH 43 . The low level of polymorphism of GZM genes in Felidae species (Table 3) is similar to the findings in dog genes.…”

“…There is only one variant known in dog genomes, despite variable positions nucleotide coding sequences (Table This observation is in agreement with the results of an analysis of another 54 individuals of Canis lupus familiaris. 42 A basic level of intraspecific variability has also been observed in camels 43 (one or two variants). Although the Felidae mostly show comparable levels of protein polymorphism with one to two allelic variants (Table 3), there are species with more variants, such as Caracal caracal (three) and Prionailurus bengalensis (four; see File S8).…”

Single-cell sequencing reveals peritoneal environment and insights into fibrosis in CAPD patients

“…Interestingly, we also found that the marker genes (GNLY, PRF1, GZMB, and NKG7) of CTLs was higher in the long-term group than those in the short-term group, the result has not been reported before. CTLs can kill target cells through the expression and release of perforin and granzymes that are encoded by GNLY, PRF1, and GZMB, 43 and GNLY can induce recruitment and activation of antigen-presenting cells (APCs) and consequently promote the generation of the immune response. 44 NKG7 is a regulator of lymphocyte granule exocytosis and downstream inflammation, 45 suggesting that CTLs activation may contribute PF after long-term PD.…”