HGNC Approved Gene Symbol: PLCZ1
Cytogenetic location: 12p12.3 Genomic coordinates (GRCh38) : 12:18,645,609-18,738,012 (from NCBI)
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
|---|---|---|---|---|
| 12p12.3 | Spermatogenic failure 17 | 617214 | Autosomal recessive | 3 |
By searching an EST database for sequences similar to PLC-delta (see 602142), followed by nested PCR and RACE, Cox et al. (2002) cloned PLCZ1 from a testis cDNA library. The deduced 608-amino acid protein has a calculated molecular mass of about 70 kD. PLCZ1 contains an N-terminal EF-hand motif, central X and Y catalytic domains, and a C-terminal C2 domain. It does not have the N-terminal pleckstrin homology domain characteristic of other PLCs. PLCZ1 shares 90% and 70% amino acid identity with simian and mouse Plcz1, respectively. The simian and mouse sequences have a longer linker region between the X and Y catalytic domains compared with human PLCZ1. Northern blot analysis detected a 2.2-kb transcript only in testis. Western blot analysis of sperm extracts found that PLCZ1 has an apparent molecular mass of about 70 kD.
Cox et al. (2002) determined that the PLCZ1 gene contains 15 exons and spans about 55 kb. Exon 1 is not translated.
By genomic sequence analysis, Cox et al. (2002) mapped the PLCZ1 gene to chromosome 12p12.3.
Cox et al. (2002) found that microinjection of cRNA for both human and simian PLCZ1 in mouse oocytes elicited Ca(2+) oscillations equivalent to those seen during fertilization in mice. Human PLCZ1 elicited mouse egg activation and early embryonic development up to the blastocyst stage. Cox et al. (2002) proposed that sperm PLCZ1 is the molecular trigger for egg activation during fertilization.
Saunders et al. (2002) showed that Plcz1 triggered Ca(2+) oscillations in mouse eggs. Removal of Plcz1 from sperm extracts abolished Ca(2+) release in eggs.
Sone et al. (2005) followed the intracellular distribution of fluorescence-tagged mouse Plcz1 RNA injected into mouse eggs. Plcz1 dispersed into the cytoplasm upon nuclear envelope breakdown and translocated into the nucleus after cleavage during the first mitosis. Likewise, Plcz1 exhibited alternative cytoplasmic/nuclear localization during the second mitosis, and this dynamic distribution continued up to the blastocyst stage. Sone et al. (2005) concluded that PLCZ1 may control cell cycle-dependent Ca(2+) oscillations in early embryogenesis.
In 2 Tunisian brothers with infertility due to oocyte activation failure (SPGF17; 617214), Escoffier et al. (2016) identified homozygosity for a missense mutation in the PLCZ1 gene (I489F; 608075.0001) that was present in heterozygosity in a fertile brother and was not found in the ExAC database.
In 4 Chinese men from 3 consanguineous families with SPGF17 and total fertilization failure of oocytes after intracytoplasmic sperm injection, Dai et al. (2020) identified homozygous mutations in the PLCZ1 gene (608075.0002-608075.0004). The mutations, which were found by whole-exome sequencing and confirmed by Sanger sequencing, were present in heterozygous state in the parents. All 3 mutations occurred in the highly conserved X or Y catalytic domains.
In each of 2 unrelated Chinese men with infertility due to acrosomal abnormalities and total fertilization failure, Zhao et al. (2023) identified compound heterozygosity for a splice site mutation and a missense variant in the PLCZ1 gene: c.1174+3A-C (608075.0005) and N425S (608075.0006) in one, and c.136-1G-C (608075.0007) and G453D (608075.0008) in the other. The mutations segregated fully with disease in each family, and were not found or were present at very low minor allele frequency in the East Asian populations of public variant databases. Patient sperm showed markedly reduced expression of PLCZ1.
In 2 unrelated Chinese men from consanguineous families, who had infertility due to total fertilization failure, Hua et al. (2023) identified homozygosity for the previously reported C196X substitution in the PLCZ1 gene (608075.0002).
Escoffier et al. (2016) analyzed PLCZ1 expression in mouse germinal-vesicle (GV) oocytes and observed homogeneous distribution in the ooplasm that partly overlapped with distribution of the endoplasmic reticulum (ER). Mutant I489F (see 608075.0001) PLCZ1 displayed an uneven distribution characterized by large patches near the nucleus and decreased peripheral localization, and the distribution did not overlap with the ER. Analysis of the corresponding mouse mutation (I527F) in mouse metaphase-II (MII) oocytes showed a lower frequency of Ca(2+) oscillation compared to wildtype, delay in pronuclei (PN) formation, and failure of the mutant protein to localize to the PN. In addition, the altered Ca(2+) signaling prevented most zygotes from cleaving past the 2-cell stage.
Nozawa et al. (2018) found that Plcz1 -/- male mice did not show defects in spermatogenesis or sperm morphology, motility, or acrosome reaction rates. Intracytoplasmic sperm injection (ICSI) using epididymal spermatozoa showed that Plcz1 -/- spermatozoa lacked the ability to induce rises in intracellular Ca(2+) in ICSI oocytes and could not activate oocytes. However, Plcz1 -/- males were not sterile, but their fecundity was reduced, as most fertilized oocytes ceased development at the 1- to 2-cell stage due to oocyte activation failure or polyspermy. In vitro fertilization (IVF) experiments revealed that fertilization rates were similar between wildtype and Plcz1 -/- spermatozoa, indicating that Plcz1 was not essential for in vivo fertilization. Furthermore, oocyte activation ability by spermatozoa was independent from Plcz1, but a single spermatozoon was insufficient and rarely triggered resumption of the meiotic cell cycle, with incomplete oocyte activation leading to polyspermy. Polyspermy in oocytes fertilized with Plcz1 -/- spermatozoa was caused by delayed zona pellucida block to polyspermy (ZPBP) and delayed plasma membrane block to polyspermy (PMBP), with the latter being more critical. Knockin male mice with Plcz1 mutations corresponding to human infertility-associated mutations in PLCZ1 phenocopied Plcz1 -/- male mice in spermatogenesis, fertility, IVF, and ICSI outcomes. However, injection of wildtype mouse Plcz1 mRNA or human PLCZ1 mRNA successfully activated mouse oocytes and restored fertility of knockin males.
In 2 Tunisian brothers, born of first-cousin parents, who were infertile due to failure of oocyte activation (SPGF17; 617214), Escoffier et al. (2016) identified homozygosity for a c.1465A-T transversion (c.1465A-T, NM_033123.3) in exon 13 of the PLCZ1 gene, resulting in an ile489-to-phe (I489F) substitution at a well-conserved residue within the lipid-binding C2 domain. The mutation was present in heterozygosity in a fertile brother and was not found in the ExAC database. In contrast to sperm from fertile controls, where a band of strong staining for PLCZ1 was observed on the postacrosomal area and more diffuse staining over the acrosome, immunofluorescence analysis of patient sperm showed no detectable staining or faint punctate staining over the acrosome. Absence of PLCZ1 in patient sperm was confirmed by Western blot. Injection of wildtype or mutated human PLCZ1 cRNA into mouse metaphase-II (MII) oocytes demonstrated initiation of high-frequency oscillations in all oocytes injected with wildtype PLCZ1, whereas the I489F mutant either failed to initiate oscillations or induced low-frequency responses. Enzymatic activity of the mutant was reduced irrespective of the concentration of cRNA injected, suggesting that trace amounts of PLCZ1 are likely not sufficient to activate oocytes. Following injection of wildtype PLCZ1, 64.6% of oocytes showed signs of activation, with formation of 2 pronuclei, and 35% reached the blastocyst stage. In contrast, the I489F mutant showed a greatly reduced ability to induce oocyte activation, resulting in fertilization of only 13.9% of oocytes, none of which developed to the blastocyst stage.
In a Chinese man, born of consanguineous parents, who was infertile due to failure of oocyte activation (SPGF17; 617214), Dai et al. (2020) identified homozygosity for a c.588C-A transversion (c.588C-A, NM_001330774) in exon 6 of the PLCZ1 gene, resulting in a cys196-to-ter (C196X) substitution in the highly conserved X catalytic domain. The mutation, which was identified by whole-exome sequencing and confirmed by Sanger sequencing, was present in heterozygous state in the parents. The variant was present at a low frequency in the gnomAD, 1000 Genomes Project, and ExAC databases. Molecular modeling predicted that the mutant protein would lose most of the catalytic and C2 domains. No PLCZ1 protein was detected in the patient's sperm by immunofluorescent staining.
In 2 unrelated Chinese men (P3 and P5) from consanguineous families, who had infertility due to total fertilization failure, Hua et al. (2023) identified homozygosity for the C196X substitution in the PLCZ1 gene. The unaffected parents in both families were heterozygous for the mutation; the fertile brother of P3 did not carry the mutation.
In a Chinese man, born of consanguineous parents, who was infertile due to failure of oocyte activation (SPGF17; 617214), Dai et al. (2020) identified homozygosity for a c.1048T-C transition (c.1048T-C, NM_001330774) in exon 10 of the PLCZ1 gene, resulting in a ser350-to-pro (S350P) substitution in the highly conserved Y catalytic domain. The mutation, which was identified by whole-exome sequencing and confirmed by Sanger sequencing, was present in heterozygous state in the parents. The variant was not reported in the gnomAD, 1000 Genomes Project, or ExAC databases. Molecular modeling predicted that the resultant protein would have an effect on hydrogen bonding and secondary structure. Abnormal localization of the PLCZ1 protein was detected in the patient's sperm by immunofluorescent staining.
In 2 Chinese sibs, born of consanguineous parents, who were infertile due to failure of oocyte activation (SPGF17; 617214), Dai et al. (2020) identified homozygosity for a c.736C-T transition (c.736C-T, NM_001330774) in exon 7 of the PLCZ1 gene, resulting in a leu246-to-phe (L246F) substitution in the highly conserved X catalytic domain. The mutation, which was identified by whole-exome sequencing and confirmed by Sanger sequencing, was present in heterozygous state in the parents. The variant was not reported in the gnomAD, 1000 Genomes Project, or ExAC databases. Molecular modeling predicted that the resultant protein would have an effect on hydrogen bonding and secondary structure. Abnormal localization of the PLCZ1 protein was detected in the patients' sperm by immunofluorescent staining.
In a 34-year-old Chinese man (case 2) with infertility due to acrosomal abnormalities and total fertilization failure (SPGF17; 617214), Zhao et al. (2023) identified compound heterozygosity for mutations in the PLCZ1 gene: a splice site mutation (c.1174+3A-C) in intron 10, and a c.1274A-G transition in exon 11, resulting in an asn425-to-ser (N425S) substitution at a conserved residue within the PI-PLC Y-box domain. His unaffected parents and older sister were each heterozygous for 1 of the mutations, which were not found in the East Asian populations of the 1000 Genomes Project or gnomAD databases. QT-PCR of patient sperm showed a marked reduction in PLCZ1 expression, by approximately two-thirds compared to control sperm.
For discussion of the c.1274A-G transition in exon 11 of the PLCZ1 gene, resulting in an asn425-to-ser (N425S) substitution, that was found in compound heterozygous state in a 34-year-old Chinese man (case 2) with infertility due to acrosomal abnormalities and total fertilization failure (SPGF17; 617214) by Zhao et al. (2023), see 608075.0005.
In a 39-year-old Chinese man (case 3) with infertility due to acrosomal abnormalities and total fertilization failure (SPGF17; 617214), Zhao et al. (2023) identified compound heterozygosity for mutations in the PLCZ1 gene: a splice site mutation (c.136-1G-C) in intron 3, and a c.1358G-A transition in exon 12, resulting in a gly453-to-asp (G453D) substitution at a conserved residue within the PI-PLC Y-box domain. His unaffected parents were each heterozygous for 1 of the mutations, which were not found in the East Asian population of the 1000 Genomes Project; however, the G453D variant was present at very low minor allele frequency (3.99 x 10(-6)) in the East Asian population of the gnomAD database.
For discussion of the c.1358G-A transition in exon 12 of the PLCZ1 gene, resulting in a gly453-to-asp (G453D) substitution, that was found in compound heterozygous state in a 39-year-old Chinese man (case 3) with infertility due to acrosomal abnormalities and total fertilization failure (SPGF17; 617214) by Zhao et al. (2023), see 608075.0007.
Cox, L. J., Larman, M. G., Saunders, C. M., Hashimoto, K., Swann, K., Lai, F. A. Sperm phospholipase C-zeta from humans and cynomolgus monkeys triggers Ca(2+) oscillations, activation and development of mouse oocytes. Reproduction 124: 611-623, 2002. [PubMed: 12416999] [Full Text: https://doi.org/10.1530/rep.0.1240611]
Dai, J., Dai, C., Guo, J., Zheng, W., Zhang, T., Li, Y., Lu, C., Gong, F., Lu, G., Li, G. Novel homozygous variations in PLCZ1 lead to poor or failed fertilization characterized by abnormal localization patterns of PLC-zeta in sperm. Clin. Genet. 97: 347-351, 2020. [PubMed: 31463947] [Full Text: https://doi.org/10.1111/cge.13636]
Escoffier, J., Lee, H. C., Yassine, S., Zouari, R., Martinez, G., Karaouzene, T., Coutton, C., Kherraf, Z., Halouani, L., Triki, C., Nef, S., Thierry-Mieg, N., Savinov, S. N., Fissore, R., Ray, P. F., Arnoult, C. Homozygous mutation of PLCZ1 leads to defective human oocyte activation and infertility that is not rescued by the WW-binding protein PAWP. Hum. Molec. Genet. 25: 878-891, 2016. [PubMed: 26721930] [Full Text: https://doi.org/10.1093/hmg/ddv617]
Hua, R., Xue, R., Liu, Y., Li, Y., Sha, X., Li, K., Gao, Y., Shen, Q., Lv, M., Xu, Y., Zhang, Z., He, X., Cao, Y., Wu, H. ACROSIN deficiency causes total fertilization failure in humans by preventing the sperm from penetrating the zona pellucida. Hum. Reprod. 38: 1213-1223, 2023. [PubMed: 37004249] [Full Text: https://doi.org/10.1093/humrep/dead059]
Nozawa, K., Satouh, Y., Fujimoto, T., Oji, A., Ikawa, M. Sperm-borne phospholipase C zeta-1 ensures monospermic fertilization in mice. Sci. Rep. 8: 1315, 2018. [PubMed: 29358633] [Full Text: https://doi.org/10.1038/s41598-018-19497-6]
Saunders, C. M., Larman, M. G., Parrington, J., Cox, L. J., Royse, J., Blayney, L. M., Swann, K., Lai, F. A. PLC-zeta: a sperm-specific trigger of Ca(2+) oscillations in eggs and embryo development. Development 129: 3533-3544, 2002. [PubMed: 12117804] [Full Text: https://doi.org/10.1242/dev.129.15.3533]
Sone, Y., Ito, M., Shirakawa, H., Shikano, T., Takeuchi, H., Kinoshita, K., Miyazaki, S. Nuclear translocation of phospholipase C-zeta, an egg-activating factor, during early embryonic development. Biochem. Biophys. Res. Commun. 330: 690-694, 2005. [PubMed: 15809052] [Full Text: https://doi.org/10.1016/j.bbrc.2005.03.032]
Zhao, S., Cui, Y., Guo, S., Liu, B., Bian, Y., Zhao, S., Chen, Z., Zhao, H. Novel variants in ACTL7A and PLCZ1 are associated with male infertility and total fertilization failure. Clin. Genet. 103: 603-608, 2023. [PubMed: 36593593] [Full Text: https://doi.org/10.1111/cge.14293]