Alternative titles; symbols
HGNC Approved Gene Symbol: GNLY
Cytogenetic location: 2p11.2 Genomic coordinates (GRCh38) : 2:85,694,358-85,698,852 (from NCBI)
The GNLY gene encodes granulysin, a member of the saposin-like protein (SAPLIP) family that is present in cytotoxic granules of cytolytic T cells (CTSs) and natural killer (NK) cells and is released from the granules upon antigen stimulation (Jongstra et al., 1987; Pena et al., 1997).
Jongstra et al. (1987) isolated 2 overlapping clones corresponding to the GNLY gene, which they termed '519,' from a human functional cytolytic T cell cDNA library. The deduced 129-residue protein has a calculated molecular mass of 14.6 kD. Northern blot analysis detected a 900-bp mRNA that was also detected in functional T-helper cell lines, but not in several T-cell tumor lines or other tissues. The findings indicated that 519 expression is restricted to IL2 (147680)-dependent, antigen-driven functional T cells. Expression of 519 was induced at least 10-fold in peripheral blood lymphocytes by antigenic or mitogenic stimulation.
Yabe et al. (1990) cloned GNLY, which they termed NKG5, from a natural killer cell cDNA library. The deduced 145-residue protein began at a start codon at position 129, with significant homology with the 519 gene reported by Jongstra et al. (1987). A sequence comparison showed that the 519 and NKG5 sequences were identical except that NKG5 lacks a 242-bp segment that is found in 519, and that this deletion leads to the use of a different putative translational start codon and different N-terminal regions. Unlike 519, the predicted NKG5 protein has a putative N-terminal signal peptide, suggesting that it is a secreted protein. In contrast, the 519 protein is hydrophilic and proposed to act intracellularly. Northern blot analysis detected 40-fold higher expression of the NKG5 transcript compared to 519 in NK and T cells. Southern blot analysis indicated that both mRNAs are transcripts from a single gene, consistent with alternative splicing. Yabe et al. (1990) concluded that the 519 transcript results from a nonproductive splicing event and does not encode a functional protein.
Houchins et al. (1993) identified many potential regulatory segments within the 5-prime flanking region of the NKG5 gene, including AP1, AP2, AP3, and SRE motifs.
Jongstra et al. (1987) identified 2 ATG translation initiation codons in the 519 gene at positions 27 and 281: the latter at 281 was presumed to be active, since the first ATG codon is followed by an in-frame stop codon at position 69.
Houchins et al. (1993) determined that the GNLY gene contains 5 exons.
By in situ hybridization, Donlon et al. (1990) assigned the GNLY gene to chromosome 2p12-q11.
Stenger et al. (1998) showed that granulysin is a critical effector molecule of the antimicrobial activity of CTLs. Cytolytic T cells are required for protective immunity against intracellular pathogens such as Listeria monocytogenes and Trypanosoma cruzi, which escape from phagocytic vacuoles into the cytoplasm of infected host cells, as well as Salmonella typhimurium, Escherichia coli, and Mycobacterium tuberculosis, which are phagocytized by macrophages and remain localized within phagosomes (Pena et al., 1997). An explanation for the functional role of CTLs in immunity against intracellular infection was provided by analysis of CTLs in tuberculosis (Kaufmann, 1988; Stenger et al., 1997). These experiments suggested that CTLs that kill infected cells through the granule-exocytosis pathway may release 1 or more effector molecules with the capacity to kill the intracellular microbial pathogen directly.
Two subsets of CTLs exist, which differ in phenotype, cytotoxic effector pathway, and antimicrobial activity. CD8+ CTLs lyse M. tuberculosis-infected macrophages by a granule-dependent mechanism that results in killing of the intracellular pathogen. In contrast, the cytotoxicity of double negative CD4-/CD8- T cells is mediated by Fas-Fas ligand interaction and does not inhibit growth of the mycobacteria. By protein immunoblot analysis, Stenger et al. (1998) demonstrated the presence of granulysin in CD8+ CTLs and the lack of granulysin expression in CD4-/CD8- CTLs. Confocal microscopy of granulysin-expressing cells showed a punctate pattern consistent with granule localization. Furthermore, double staining of CD8+ T cells with antibodies against granulysin and perforin (PRF1; 170280), a molecule known to be expressed in cytotoxic granules, showed substantial colocalization. Stenger et al. (1998) used recombinant granulysin to test directly its antimicrobial activity against M. tuberculosis and other organisms.
Chung et al. (2008) showed that blister cells from skin lesions from patients with Stevens-Johnson syndrome (SJS) or toxic epidermolysis necrosis (TEN) (see 608579) primarily consisted of cytotoxic T lymphocytes and natural killer cells, and that both blister fluids and cells were cytotoxic. Gene expression profiling identified granulysin as the most highly expressed cytotoxic molecule, confirmed by quantitative PCR and immunohistochemistry. Depletion of granulysin reduced cytotoxicity. In blister fluids, granulysin was in a 15-kD secretory form, and injection of this form into mouse skin resulted in features mimicking the skin necrosis. Chung et al. (2008) concluded that secretory granulysin is a key molecule responsible for the disseminated keratinocyte death in SJS/TEN. The findings also implicated a CTL- or NK cell-mediated cytotoxicity that does not require direct cellular contact.
Associations Pending Confirmation
For a discussion of a possible association between susceptibility to toxic epidermal necrolysis (see 608579) and variation in the GNLY gene, see 188855.0001.
This variant is classified as a variant of unknown significance because its contribution to toxic epidermal necrolysis (see 608579) has not been confirmed.
Fonseca et al. (2019) sequenced the GNLY gene in 19 Colombian patients with Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN), and identified a 59-year-old woman (patient SJS-3) with TEN who was heterozygous for a c.11G-A transition (c.11G-A, NM_006433) resulting in a trp4-to-ter (W4X) substitution. The variant was not found in 99 Colombian individuals who had taken phenytoin for at least 6 months, or in 150 healthy Colombian women from the same region of the country as patient SJS-3, but was present in the gnomAD database with a minor allele frequency of 0.08464, including 95 homozygotes. Familial segregation was not reported. The proband developed TEN after taking metoclopramide, experiencing fever as well as a rash with small blisters that covered 95% of her body surface area, with intraoral and ocular mucosal involvement. Studies in transfected CHO cells demonstrated that the W4X mutant had exclusive nuclear subcellular localization, in contrast to wildtype GNLY, which showed diffuse cytoplasmic localization.
Chung, W.-H., Hung, S.-I., Yang, J.-Y., Su, S.-C., Huang, S.-P., Wei, C.-Y., Chin, S.-W., Chiou, C.-C., Chu, S.-C., Ho, H.-C., Yang, C.-H., Lu, C.-F., Wu, J.-Y., Liao, Y.-D., Chen, Y.-T. Granulysin is a key mediator for disseminated keratinocyte death in Stevens-Johnson syndrome and toxic epidermal necrolysis. Nature Med. 14: 1343-1350, 2008. [PubMed: 19029983] [Full Text: https://doi.org/10.1038/nm.1884]
Donlon, T. A., Krensky, A. M., Clayberger, C. Localization of the human T lymphocyte activation gene 519 (D2S69E) to chromosome 2p12-q11. Cytogenet. Cell Genet. 53: 230-231, 1990. [PubMed: 2209093] [Full Text: https://doi.org/10.1159/000132938]
Fonseca, D. J., Caro, L. A., Sierra-Diaz, D. C., Serrano-Reyes, C., Londono, O., Suarez, Y. C., Mateus, H. E., Bolivar-Salazar, D., Ramirez, A. F., de-la-Torre, A., Laissue, P. Mutant GNLY is linked to Stevens-Johnson syndrome and toxic epidermal necrolysis. Hum. Genet. 138: 1267-1274, 2019. [PubMed: 31642954] [Full Text: https://doi.org/10.1007/s00439-019-02066-w]
Houchins, J. P., Kricek, F., Chujor, C. S. N., Heise, C. P., Yabe, T., McSherry, C., Bach, F. H. Genomic structure of NKG5, a human NK and T cell-specific activation gene. Immunogenetics 37: 102-107, 1993. [PubMed: 8423048] [Full Text: https://doi.org/10.1007/BF00216832]
Jongstra, J., Schall, T. J., Dyer, B. J., Clayberger, C., Jorgensen, J., Davis, M. M., Krensky, A. M. The isolation and sequence of a novel gene from a human functional T cell line. J. Exp. Med. 165: 601-614, 1987. [PubMed: 2434598] [Full Text: https://doi.org/10.1084/jem.165.3.601]
Kaufmann, S. H. E. CD8+ T lymphocytes in intracellular microbial infections. Immun. Today 9: 168-174, 1988. [PubMed: 3151440] [Full Text: https://doi.org/10.1016/0167-5699(88)91292-3]
Pena, S. V., Hanson, D. A., Carr, B. A., Goralski, T. J., Krensky, A. M. Processing, subcellular localization, and function of 519 (granulysin), a human late T cell activation molecule with homology to small, lytic granule proteins. J. Immun. 158: 2680-2688, 1997. [PubMed: 9058801]
Stenger, S., Hanson, D. A., Teitelbaum, R., Dewan, P., Niazi, K. R., Froelich, C. J., Ganz, T., Thoma-Uszynski, S., Melian, A., Bogdan, C., Porcelli, S. A., Bloom, B. R., Krensky, A. M., Modlin, R. L. An antimicrobial activity of cytolytic T cells mediated by granulysin. Science 282: 121-125, 1998. [PubMed: 9756476] [Full Text: https://doi.org/10.1126/science.282.5386.121]
Stenger, S., Mazzaccaro, R. J., Uyemura, K., Cho, S., Barnes, P. F., Rosat, J. P., Sette, A., Brenner, M. B., Porcelli, S. A., Bloom, B. R., Modlin, R. L. Differential effects of cytolytic T cell subsets on intracellular infection. Science 276: 1684-1687, 1997. [PubMed: 9180075] [Full Text: https://doi.org/10.1126/science.276.5319.1684]
Yabe, T., McSherry, C., Bach, F. H., Houchins, J. P. A cDNA clone expressed in natural killer and T cells that likely encodes a secreted protein. J. Exp. Med. 172: 1159-1163, 1990. [PubMed: 2212946] [Full Text: https://doi.org/10.1084/jem.172.4.1159]