Potassium Channel Tetramerization Domain Research Articles

Expression of variant transcripts of the potassium channel tetramerization domain-containing 15 (KCTD15) gene and their association with fatness traits in chickens

The aim of this study was to characterize the structure, expression, and biological functions of potassium channel tetramerization domain containing 15 (KCTD15) in chickens. We compared the KCTD15 expression level in samples of hypothalamic, adipose, and liver tissue of Xinghua chickens that were maintained on different dietary status. An association analysis of KCTD15 gene variant transcripts with fatness traits in a F2 resource population of chickens was performed. Three KCTD15 transcripts were identified in which the complete transcript was predominantly expressed in adipose tissue and the hypothalamus. The chicken KCTD15 gene was regulated by both feeding and fasting and consumption of a high-fat diet. The expression level of KCTD15 gene was markedly decreased in hypothalamus and liver of fasted and refed chickens (P < 0.05) and significantly downregulated in adipose tissue by the high-fat diet (P < 0.05). Three single-nucleotide polymorphisms of the KCTD15 gene were significantly associated with a number of fatness traits in chicken (P < 0.05). These results suggest that KCTD15 have a potential role regulation of obesity and fat metabolism in chickens.

Targeted disruption of the mouse testis-enriched gene Znf230 does not affect spermatogenesis or fertility.

The mouse testis-enriched Znf230 gene, which encodes a type of RING finger protein, is present primarily in the nuclei of spermatogonia, the acrosome and the tail of spermatozoa. To investigate the role of Znf230 in spermatogenesis, we generated Znf230-deficient mice by disrupting Znf230 exon-5 and exon-6 using homologous recombination. The homozygous Znf230-knockout (KO) mice did not exhibit Znf230 mRNA expression and Znf230 protein production. Znf230 KO mice exhibited no obvious impairment in body growth or fertility. Male Znf230 KO mice had integral reproductive systems and mature sperm that were regular in number and shape. The developmental stages of male germ cells of Znf230 KO mice were also normal. We further examined variations in the transcriptomes of testicular tissue between Znf230 KO and wild-type mice through microarray analysis. The results showed that the mRNA level of one unclassified transcript 4921513I08Rik was increased and that the mRNA levels of three other transcripts, i.e., 4930448A20Rik, 4931431B13Rik and potassium channel tetramerisation domain containing 14(Kctd14), were reduced more than two-fold in Znf230 KO mice compared with wild-type mice. Using our current examination techniques, these findings suggested that Znf230 deficiency in mice may not affect growth, fertility or spermatogenesis.

Kctd10 regulates heart morphogenesis by repressing the transcriptional activity of Tbx5a in zebrafish

The T-box transcription factor Tbx5 (Tbx5a in zebrafish) plays a crucial role in the formation of cardiac chambers in a dose-dependent manner. Its deregulation leads to congenital heart disease. However, little is known regarding its regulation. Here we isolate a zebrafish mutant with heart malformations, called 34c. The affected gene is identified as kctd10, a member of the potassium channel tetramerization domain (KCTD)-containing family. In the mutant, the expressions of the atrioventricular canal marker genes, such as tbx2b, hyaluronan synthase 2 (has2), notch1b and bmp4, are changed. The knockdown of tbx5 rescues the ectopic expression of has2, and knockdown of either tbx5a or has2 alleviates the heart defects. We show that Kctd10 directly binds to Tbx5 to repress its transcriptional activity. Our results reveal a new essential factor for cardiac development and suggest that KCTD10 could be considered as a new causative gene of congenital heart disease.

The BTB-Containing Protein Kctd15 Is SUMOylated In Vivo

Potassium Channel Tetramerization Domain containing 15 (Kctd15) has a role in regulating the neural crest (NC) domain in the embryo. Kctd15 inhibits NC induction by antagonizing Wnt signaling and by interaction with the transcription factor AP-2α activation domain blocking its activity. Here we demonstrate that Kctd15 is SUMOylated by SUMO1 and SUMO2/3. Kctd15 contains a classical SUMO interacting motif, ψKxE, at the C-terminal end, and variants of the motif within the molecule. Kctd15 SUMOylation occurs exclusively in the C-terminal motif. Inability to be SUMOylated did not affect Kctd15's subcellular localization, or its ability to repress AP-2 transcriptional activity and to inhibit NC formation in zebrafish embryos. In contrast, a fusion of Kctd15 and SUMO had little effectiveness in AP-2 inhibition and in blocking of NC formation. These data suggest that the non-SUMOylated form of Kctd15 functions in NC development.

Gene Expression Network Analysis of ETV1 Reveals KCTD10 as a Novel Prognostic Biomarker in Gastrointestinal Stromal Tumor

BackgroundPrognostic biomarkers are required for risk stratification therapy in the patients with gastrointestinal stromal tumor (GIST). In this study, we aimed to identify prognostic biomarkers in GIST. We assessed the prognostic value of E twenty-six variant 1 (ETV1), a recently identified transcription factor unique to GIST. We also examined the clinical utility and functions of its downstream gene, potassium channel tetramerization domain containing protein 10 (KCTD10).MethodsThe levels of ETV1 and KCTD10 were evaluated immunohistochemically in 112 patients with GIST treated at two hospitals. The functional properties of KCTD10 were examined by gene silencing assay in cultured GIST cells.ResultsImmunohistochemistry revealed that ETV1 expression in GIST had no prognostic significance. In contrast, the disease-free survival rate was 88.5% in patients with KCTD10-positive tumors and 55.8% in those with KCTD10-negative tumors (p <0.0001). KCTD10 was an independent prognostic factor (p <0.05). In the low-risk classification group, KCTD10 was significantly associated with favorable prognosis (p = 0.0008). Gene silencing of KCTD10 increased cell proliferation and invasion, suggesting that KCTD10 has a tumor-suppressive function.ConclusionsThe GIST-specific transcription factor ETV1 may have no prognostic potential, whereas its downstream gene KCTD10 is associated with a favorable prognosis. Our study indicated the novel prognostic utility of KCTD10 in GIST, and suggested its tumor-suppressive effects on GIST cells. Further validation studies of KCTD10 for clinical applications, and functional verification of KCTD10 for better understanding of molecular basis of malignant phenotypes are worth challenging in GIST.

Inhibition of neural crest formation by Kctd15 involves regulation of transcription factor AP-2

The neural crest develops in vertebrate embryos within a discrete domain at the neural plate boundary and eventually gives rise to a migrating population of cells that differentiate into a multitude of derivatives. We have shown that the broad-complex, tramtrack and bric a brac (BTB) domain-containing factor potassium channel tetramerization domain containing 15 (Kctd15) inhibits neural crest formation, and we proposed that its function is to delimit the neural crest domain. Here we report that Kctd15 is a highly effective inhibitor of transcription factor activating enhancer binding protein 2 (AP-2) in zebrafish embryos and in human cells; AP-2 is known to be critical for several steps of neural crest development. Kctd15 interacts with AP-2α but does not interfere with its nuclear localization or binding to cognate sites in the genome. Kctd15 binds specifically to the activation domain of AP-2α and efficiently inhibits transcriptional activation by a hybrid protein composed of the regulatory protein Gal4 DNA binding and AP-2α activation domains. Mutation of one proline residue in the activation domain to an alanine (P59A) yields a protein that is highly active but largely insensitive to Kctd15. These results indicate that Kctd15 acts in the embryo at least in part by specifically binding to the activation domain of AP-2α, thereby blocking the function of this critical factor in the neural crest induction hierarchy.

KCTD9 contributes to liver injury through NK cell activation during hepatitis B virus-induced acute-on-chronic liver failure

We explored the expression of a newly identified potassium channel tetramerisation domain containing 9 (KCTD9) protein in 113 blood and 81 liver samples, from patients with mild chronic hepatitis B (CHB) or HBV-induced acute-on-chronic liver failure (HBV-ACLF). KCTD9 was highly expressed in peripheral and hepatic NK cells from HBV-ACLF patients compared with mild CHB patients, and this correlated positively with the severity of liver injury. The role of KCTD9 was further investigated in NK92 cells in vitro. KCTD9 overexpressed NK92 cells exhibited a marked increase in CD69 expression, cytotoxicity, IFN-γ secretion and a significant decrease in NKG2A receptor expression. Inhibition of KCTD9 by shRNA resulted in reduced cytotoxic function. These results suggest the involvement of KCTD9 in NK cell activation and provide additional insight into a potential therapeutic target for molecular manipulation for HBV-ACLF patients.

Proteomic approach toward personalized sarcoma treatment: Lessons from prognostic biomarker discovery in gastrointestinal stromal tumor

Sarcomas range from curable tumors to those causing death via metastasis and recurrence. Thus, there is an urgent need for biomarker identification in order to assess the degree of malignancy, predict prognosis, and evaluate possible therapies. Various proteomic approaches and different clinical materials have been used to this end, and candidate biomarkers have been reported for the different types of sarcomas. However, the sample size used in these biomarker studies was generally insufficient, and thus far, no biomarker has been proved useful in clinics. Given that sarcomas are rare, biomarker validation in this setting is more challenging than in other malignancies. In gastrointestinal stromal tumor, adjuvant therapy has proven to be effective. However, only 40% patients experience metastasis after curative surgery alone, and the rest of the patients may not need adjuvant therapy. Using a proteomic approach, we identified pfetin (potassium channel tetramerization domain containing 12, KCTD 12) as a novel prognostic biomarker for sarcoma, and immunohistochemically confirmed its clinical usefulness by a multiinstitutional validation study. Here, we describe our experience and discuss the critical points in the discovery of this biomarker.

Expression, purification, and secondary structure characterization of recombinant KCTD1

Potassium channel tetramerization domain containing 1 (KCTD1) contains a BTB domain, which can facilitate protein-protein interactions that may be involved in the regulation of signaling pathways. Here we describe an expression and purification system that can provide a significant amount of recombinant KCTD1 from Escherichia coli. The cDNA encoding human KCTD1 was amplified and cloned into the expression vector pET-30a(+). The recombinant protein was expressed in E. coli BL21(DE3) cells and subsequently purified using affinity chromatography. To confirm that KCTD1 was correctly expressed and folded, the molecular weight and conformation were analyzed using mass spectroscopy, Western blot, and circular dichroism. Optimizing KCTD1 expression and investigating its secondary structure will provide valuable information for future structural and functional studies of KCTD1 and KCTD family proteins.

TNFAIP1 interacts with KCTD10 to promote the degradation of KCTD10 proteins and inhibit the transcriptional activities of NF-κB and AP-1

The broad-complex, tramtrack, and bric-a-brac/poxvirus and zinc finger domain-containing protein tumor necrosis factor, alpha-induced protein 1 (TNFAIP1) was first identified as a gene whose expression can be induced by the tumor necrosis factor alpha. Some studies showed that TNFAIP1 may function in DNA replication, apoptosis and human diseases. However, the definite functions and the mechanisms of TNFAIP1 are poorly known. In this study, we performed a yeast two-hybrid assay and used TNFAIP1 as the bait to screen human brain cDNA library. Potassium channel tetramerisation domain containing 10 (KCTD10) was identified as TNFAIP1-interacting partner. The KCTD10-TNFAIP1 interaction was then confirmed by the in vitro GST pull-down assays and the in vivo co-immunoprecipitation and colocalization assays. In addition, protein degradation and ubiquitin assays revealed TNFAIP1 overexpression resulted in ubiquitin-mediated degradation of KCTD10 proteins, which was significantly alleviated with the proteasome inhibitor MG132 treatment. Furthermore, transient transfection assays with two reporters showed that TNFAIP1 and KCTD10 inhibited the transcriptional activities of nuclear factor kappa B (NF-κB) and activating protein-1 reporters. Taken together, our results indicated the novel interaction and function between KCTD10 and TNFAIP1 in human PDIP1 family.

Novel Mutation in Potassium Channel related Gene KCTD7 and Progressive Myoclonic Epilepsy

Progressive myoclonic epilepsy (PME) is a heterogeneous group of epilepsies characterized by myoclonus, seizures and progressive neurological symptoms. The index patient was a 6-year old boy showing early-onset therapy resistant PME and severe developmental delay. Genome-wide linkage analysis identified several candidate regions. The potassium channel tetramerization domain containing 7 gene (KCTD7) in the 7q11.21 linkage region emerged as a suitable candidate. Sequence analysis revealed a novel homozygous missense mutation (p.R94W) in a highly conserved segment of exon 2. This is the second family with PME caused by KCTD7 mutations, hence KCTD7 mutations might be a recurrent cause of PME.

Obscurin and KCTD6 regulate cullin-dependent small ankyrin-1 (sAnk1.5) protein turnover

Protein turnover through cullin-3 is tightly regulated by posttranslational modifications, the COP9 signalosome, and BTB/POZ-domain proteins that link cullin-3 to specific substrates for ubiquitylation. In this paper, we report how potassium channel tetramerization domain containing 6 (KCTD6) represents a novel substrate adaptor for cullin-3, effectively regulating protein levels of the muscle small ankyrin-1 isoform 5 (sAnk1.5). Binding of sAnk1.5 to KCTD6, and its subsequent turnover is regulated through posttranslational modification by nedd8, ubiquitin, and acetylation of C-terminal lysine residues. The presence of the sAnk1.5 binding partner obscurin, and mutation of lysine residues increased sAnk1.5 protein levels, as did knockdown of KCTD6 in cardiomyocytes. Obscurin knockout muscle displayed reduced sAnk1.5 levels and mislocalization of the sAnk1.5/KCTD6 complex. Scaffolding functions of obscurin may therefore prevent activation of the cullin-mediated protein degradation machinery and ubiquitylation of sAnk1.5 through sequestration of sAnk1.5/KCTD6 at the sarcomeric M-band, away from the Z-disk-associated cullin-3. The interaction of KCTD6 with ankyrin-1 may have implications beyond muscle for hereditary spherocytosis, as KCTD6 is also present in erythrocytes, and erythrocyte ankyrin isoforms contain its mapped minimal binding site.

Zebrafish enhancer trap line showing maternal and neural expression of kctd15a

Potassium channel tetramerization domain containing proteins (KCTDs), which share a conserved BTB (Bric-a-brac, Tramtrack, Broad complex) domain at their N-terminus, are known to be involved in both developmental and neural processes. However, the developmental expression patterns and functional roles of most vertebrate KCTDs remain unknown. Using enhancer-trapping technology, we have identified a transgenic zebrafish line (ub49) where the vector insertion is in close proximity to kctd15a, and where transgenic marker (eGFP) expression closely reflects endogenous kctd15a expression. Both ub49 and kctd15a show strong maternal expression that suggests a functional role during epiboly and gastrulation. At later developmental stages, expression of eGFP in ub49 also shares the same spatiotemporal features as kctd15a in several neural tissues, including cranial placode precursors, retina, and different areas of the developing brain. In the retina, we observed eGFP labeling of the inner nuclear layer (INL), including a heterogenous population of amacrine cells, and both laminae of the inner plexiform layer (IPL). This expression pattern suggests that Kctd15a proteins have several context-dependent functional roles in both developmental and neural processes. The enhancer trap line, which is the first transgenic reporter of Kctd gene expression in vertebrates, also provides a novel tool to study kctd15a function in vivo.

Identification and characterization of Xenopus kctd15, an ectodermal gene repressed by the FGF pathway

The FGF pathway regulates a variety of developmental processes in animals through activation and/or repression of numerous target genes. Here we have identified a Xenopus homolog of potassium channel tetramerization domain containing 15 (KCTD15) as an FGF-repressed gene. Kctd15 expression is first detected at the gastrula stage and gradually increases until the tadpole stage. Whole-mount in situ hybridization reveals that the spatial expression of kctd15 is tightly regulated during early embryogenesis. While kctd15 is uniformly expressed throughout the presumptive ectoderm at the early gastrula stage, its expression becomes restricted to the non-neural ectoderm and is excluded from the neural plate at the early neurula stage. At the mid-neurula stage, kctd15 shows a more restricted distribution pattern in regions that are located at the anterior, lateral or medial edge of the neural fold, including the preplacodal ectoderm, the craniofacial neural crest and the prospective roof plate. At the tailbud stage, kctd15 expression is mainly detected in neural crest- or placode-derived tissues that are located around the eye, including the mandibular arch, trigeminal ganglia and the olfactory placode. FGF represses kctd15 expression in ectodermal explants, and the inhibition of FGF receptor with a chemical compound dramatically expands the region expressing kctd15 in whole embryos. Dorsal depletion of kctd15 in Xenopus embryos leads to bent axes with reduced head structures, defective eyes and abnormal somites, while ventral depletion causes defects in ventral and caudal morphologies. These results suggest that kctd15 is an FGF-repressed ectodermal gene required for both dorsal and ventral development.

Proteome profiling of spinal cord and dorsal root ganglia in rats with trinitrobenzene sulfonic acid-induced colitis

To investigate proteomic changes in spinal cord and dorsal root ganglia (DRG) of rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis. The colonic myeloperoxidase (MPO) activity and tumor necrosis factor-α (TNF-α) level were determined. A two-dimensional electrophoresis (2-DE)-based proteomic technique was used to profile the global protein expression changes in the DRG and spinal cord of the rats with acute colitis induced by intra-colonic injection of TNBS. TNBS group showed significantly elevated colonic MPO activity and increased TNF-α level. The proteins derived from lumbosacral enlargement of the spinal cord and DRG were resolved by 2-DE; and 26 and 19 proteins that displayed significantly different expression levels in the DRG and spinal cord were identified respectively. Altered proteins were found to be involved in a number of biological functions, such as inflammation/immunity, cell signaling, redox regulation, sulfate transport and cellular metabolism. The overexpression of the protein similar to potassium channel tetramerisation domain containing protein 12 (Kctd 12) and low expression of proteasome subunit α type-1 (psma) were validated by Western blotting analysis. TNBS-induced colitis has a profound impact on protein profiling in the nervous system. This result helps understand the neurological pathogenesis of inflammatory bowel disease.

KCTD8 Gene and Brain Growth in Adverse Intrauterine Environment: A Genome-wide Association Study

The most dramatic growth of the human brain occurs in utero and during the first 2 years of postnatal life. Genesis of the cerebral cortex involves cell proliferation, migration, and apoptosis, all of which may be influenced by prenatal environment. Here, we show that variation in KCTD8 (potassium channel tetramerization domain 8) is associated with brain size in female adolescents (rs716890, P = 5.40 × 10(-09)). Furthermore, we found that the KCTD8 locus interacts with prenatal exposure to maternal cigarette smoking vis-à-vis cortical area and cortical folding: In exposed girls only, the KCTD8 locus explains up to 21% of variance. Using head circumference as a proxy of brain size at 7 years of age, we have replicated this gene-environment interaction in an independent sample. We speculate that KCTD8 might modulate adverse effects of smoking during pregnancy on brain development via apoptosis triggered by low intracellular levels of potassium, possibly reducing the number of progenitor cells.

PrPC interacts with potassium channel tetramerization domain containing 1 (KCTD1) protein through the PrP51-136 region containing octapeptide repeats

To identify molecular interaction partners of the cellular prion protein (PrPC), we applied a yeast two-hybrid screen on a bovine brain cDNA expression library and identified the potassium channel tetramerization domain containing 1 (KCTD1) as a PrPC interacting protein. Deletion mapping showed that PrPC specifically binds KCTD1 through the unstructured PrP51-136 region. We further confirmed the interaction between PrPC and KCDT1 protein by co-immunoprecipitation in vivo and by a biosensor assay in vitro. Interestingly, the binding of an insertion mutant PrP8OR to KCTD1 is higher than that of wild-type PrPC, suggesting an important role for an unstructured region harboring octapeptide repeats in the KCTD1-PrPC interaction. Our results identify a novel PrPC-interacting protein and suggest a new approach to investigating the unidentified physiological cellular function of PrPC.

Molecular organization of the cullin E3 ligase adaptor KCTD11

The family of human proteins containing a potassium channel tetramerization domain (KCTD) includes 21 members whose function is largely unknown. Recent reports have however suggested that these proteins are implicated in very important biological processes. KCTD11/REN, the best-characterized member of the family to date, plays a crucial role in the ubiquitination of HDAC1 by acting, in complex with Cullin3, as an E3 ubiquitin ligase. By combining bioinformatics and mutagenesis analyses, here we show that the protein is expressed in two alternative variants: a short previously characterized form (sKCTD11) composed by 232 amino acids and a longer variant (lKCTD11) which contains an N-terminal extension of 39 residues. Interestingly, we demonstrate that lKCTD11 starts with a non-canonical AUU codon. Although both sKCTD11 and lKCTD11 bear a POZ/BTB domain in their N-terminal region, this domain is complete only in the long form. Indeed, sKCTD11 presents an incomplete POZ/BTB domain. Nonetheless, sKCTD11 is still able to bind Cul3, although to much lesser extent than lKCTD11, and to perform its biological activity. The heterologous expression of sKCTD11 and lKCTD11 and their individual domains in Escherichia coli yielded soluble products as fusion proteins only for the longer form. In contrast to the closely related KCTD5 which is pentameric, the characterization of both lKCTD11 and its POZ/BTB domain by gel filtration and light scattering indicates that the protein likely forms stable tetramers. In line with this result, experiments conducted in cells show that the active protein is not monomeric. Based on these findings, homology-based models were built for lKCTD11 BTB and for its complex with Cul3. These analyses indicate that a stable lKCTD11 BTB-Cul3 three-dimensional model with a 4:4 stoichiometry can be generated. Moreover, these models provide insights into the determinants of the tetramer stability and into the regions involved in lKCTD11-Cul3 recognition.

KCTD9, a novel potassium channel related gene, was highly expressed in hepatic NK cells and T cells of fulminant hepatitis mice induced by MHV-3

To explore the mechanisms of a novel potassium channel gene named KCTD9 (potassium channel tetramerization domain containing 9) in model of fulminant viral hepatitis induced by murine hepatitis virus 3 (MHV-3). 78 BALB/cJ mice(6 male) were randomly and equally assigned to two groups, model group of fulminant viral hepatitis induced by MHV3 and its control. 75 C3H/HeJ female mice were done into two groups, 39 for model group of chronic hepatitis induced by MHV3, 36 for control. Various samples including spleen, liver and lymphocytes from mice of two model groups and the controls were examined for KCTD9 expression by real time quantitative PCR and Immunohistochemistry. Independent-samples T test or one-way ANOVA were carried out in different groups. Increased expressions of KCTD9 mRNA was observed in livers of both model mice of fulminant viral hepatitis and chronic hepatitis. Compared with the control mice, the expressions of KCTD9 mRNA were up-regulated by 577.1-, 8.8-, 59.4- and 10.8-fold in hepatic NK cells, CD4+ T cells, CD8+ T cells and splenic NK cells respectively in model mice of fulminant viral hepatitis 48 hr post MHV-3 infection, whereas down-regulation by 43% and 69% in splenic CD4 + T cells and CD8+ T cells were found respectively. In contrast, in model mice of chronic viral hepatitis the expressions of KCTD9 mRNA were down-regulated by 71% and 51% in hepatic CD4+ T cells and NK cells, respectively. The expression of KCTD9 protein was mainly evidenced in infiltrative mononuclear cells of liver as shown by immunohistochemistry. Basal expression was also investigated and showed constitutive expression of KCTD9 in brain, thymus and other organs in BALB/cJ mice. A novel potassium channel gene KCTD9 was highly expressed in hepatic NK cells and T cells of fulminant hepatitis mice induced by MHV-3.

Crypton transposons: identification of new diverse families and ancient domestication events

Background"Domestication" of transposable elements (TEs) led to evolutionary breakthroughs such as the origin of telomerase and the vertebrate adaptive immune system. These breakthroughs were accomplished by the adaptation of molecular functions essential for TEs, such as reverse transcription, DNA cutting and ligation or DNA binding. Cryptons represent a unique class of DNA transposons using tyrosine recombinase (YR) to cut and rejoin the recombining DNA molecules. Cryptons were originally identified in fungi and later in the sea anemone, sea urchin and insects.ResultsHerein we report new Cryptons from animals, fungi, oomycetes and diatom, as well as widely conserved genes derived from ancient Crypton domestication events. Phylogenetic analysis based on the YR sequences supports four deep divisions of Crypton elements. We found that the domain of unknown function 3504 (DUF3504) in eukaryotes is derived from Crypton YR. DUF3504 is similar to YR but lacks most of the residues of the catalytic tetrad (R-H-R-Y). Genes containing the DUF3504 domain are potassium channel tetramerization domain containing 1 (KCTD1), KIAA1958, zinc finger MYM type 2 (ZMYM2), ZMYM3, ZMYM4, glutamine-rich protein 1 (QRICH1) and "without children" (WOC). The DUF3504 genes are highly conserved and are found in almost all jawed vertebrates. The sequence, domain structure, intron positions and synteny blocks support the view that ZMYM2, ZMYM3, ZMYM4, and possibly QRICH1, were derived from WOC through two rounds of genome duplication in early vertebrate evolution. WOC is observed widely among bilaterians. There could be four independent events of Crypton domestication, and one of them, generating WOC/ZMYM, predated the birth of bilaterian animals. This is the third-oldest domestication event known to date, following the domestication generating telomerase reverse transcriptase (TERT) and Prp8. Many Crypton-derived genes are transcriptional regulators with additional DNA-binding domains, and the acquisition of the DUF3504 domain could have added new regulatory pathways via protein-DNA or protein-protein interactions.ConclusionsCryptons have contributed to animal evolution through domestication of their YR sequences. The DUF3504 domains are domesticated YRs of animal Crypton elements.