# TNP1 Gene: Structure, Function, and Clinical Significance ## Key Takeaways - **TNP1 is a critical architectural protein in spermiogenesis, essential for histone displacement and chromatin compaction.** It facilitates the transition from histone-bound to protamine-bound DNA, a process vital for producing functionally competent spermatozoa. Dysregulation of TNP1 is strongly linked to male infertility, abnormal sperm morphology, and reduced fertilization potential. - **The *TNP1* gene is intronless and tightly regulated at the transcriptional level, primarily in round and elongating spermatids.** Its promoter contains a TATA box and a CRE element, binding the master regulator CREM, which is activated by the FSH/cAMP/PKA pathway. Epigenetic control by JHDM2A, which removes repressive histone marks, is also crucial for *TNP1* activation. - **TNP1 is a small, arginine- and lysine-rich, intrinsically disordered protein that undergoes a disorder-to-order transition upon DNA binding.** Its high positive charge neutralizes DNA's negative backbone, promoting chromatin condensation. Post-translational phosphorylation and dephosphorylation cycles dynamically regulate its DNA-binding affinity and function during spermiogenesis. - **Mutations and polymorphisms in the *TNP1* gene are directly associated with male infertility, including azoospermia, oligozoospermia, and teratozoospermia.** Specific haplotypes and missense/nonsense mutations can lead to abnormal chromatin structure, increased sperm DNA fragmentation, and reduced fertilization capacity, making TNP1 a potential biomarker for fertilization failure. - **Aberrant *TNP1* expression is observed in certain cancers as a cancer/testis (CT) antigen, suggesting potential roles in tumor biology and immunotherapy.** Furthermore, environmental factors like microplastics, ionizing radiation, and tobacco smoke can negatively impact *TNP1* expression, contributing to male reproductive impairment. --- ## Executive Summary & Key Metadata The **TNP1** gene encodes Transition Nuclear Protein 1 (also known as TP1), a small, highly basic protein that is transiently expressed during mammalian spermiogenesis. TNP1 is a principal architectural component of the condensing spermatid chromatin, where it facilitates the displacement of histones and initiates the chromatin compaction cascade that ultimately results in the hypercondensed sperm nucleus [1]. The protein is a critical intermediary in the histone-to-protamine transition, a process essential for the production of functionally competent spermatozoa. Deficiencies, mutations, or dysregulation of TNP1 are strongly associated with male infertility, abnormal sperm morphology, and reduced fertilization potential [2, 3, 4, 5, 6]. | **Attribute** | **Detail** | | :--- | :--- | | **HGNC Symbol** | TNP1 | | **UniProt Accession** | P09430 | | **Representative PDB ID** | true (Structural models available via homology; see Section 2) | | **Chromosomal Locus** | Human Chromosome 2q35 (2q34-q36 region) [7, 8] | | **Primary Molecular Function** | DNA binding; chromatin organization; histone displacement during spermiogenesis [1, 6] | | **Disease & Pathology Associations** | Male infertility (azoospermia, oligozoospermia, teratozoospermia), fertilization failure, varicocele-associated infertility [2, 4, 5, 9] | --- ## 1. Genomic Locus, Chromosomal Organization & Isoforms ### 1.1 Chromosomal Assignment and Synteny The human *TNP1* gene is localized to the long arm of chromosome 2, specifically at cytogenetic band **2q35**. This assignment was initially established through a combination of somatic cell hybrid analysis and *in situ* hybridization techniques [7]. The gene resides within a conserved genomic region that has been mapped across multiple mammalian species, underscoring its evolutionary importance. Comparative gene mapping has revealed a conserved rearrangement relative to the human genome in cattle and sheep, where *TNP1* is part of a syntenic group that includes *PROC*, *EN1*, *ALPI*, and *IL1B* [10]. In cattle, the gene has been assigned to the U17 synteny group [11], and in pigs, it is localized to Chromosome 15q24–q25 [12]. The rat *Tnp1* gene has been mapped to Chromosome 9, alongside other spermatid-specific genes such as *Acr*, *Tnp2*, and *Prm1* [13]. This clustering of spermatid-specific genes is a recurring theme in mammalian genomes; for instance, *PRM1*, *PRM2*, and *TNP2* are tightly linked in a cluster, although *TNP1* is located separately [14, 15]. ### 1.2 Gene Structure and Nucleotide Sequence The human *TNP1* gene is a single-copy, intronless gene. The absence of introns is a characteristic feature of several genes encoding structural proteins of the sperm nucleus, including the protamines. The complete nucleotide sequence of the human *TNP1* gene was determined in the early 1990s, revealing a coding region of approximately 540 base pairs that translates into a protein of 73 amino acids [7]. The gene's promoter region is relatively compact but contains critical regulatory elements that dictate its precise, stage-specific expression during spermatogenesis. ### 1.3 Promoter Architecture and Transcription Factor Binding Sites The expression of *TNP1* is tightly regulated at the transcriptional level, occurring exclusively in round and elongating spermatids. The proximal promoter contains a canonical **TATA box** and a **cAMP-responsive element (CRE)**. The CRE is a critical regulatory node, serving as the binding site for the **cAMP-responsive element modulator (CREM)** [16]. CREM is a master transcriptional regulator of spermiogenesis, and its alternative splicing and post-translational modifications are essential for the activation of a vast array of haploid-expressed genes, including *TNP1*, *PRM1*, and *PRM2*. In men with round-spermatid maturation arrest, a condition characterized by a block in spermiogenesis, *TNP1* expression is significantly reduced in parallel with reduced CREM expression, directly implicating the CREM-TNP1 axis in this pathology [16, 17]. Beyond CREM, the promoter region is also a target for other transcription factors. The histone demethylase **JHDM2A (JMJD1A)** has been shown to directly bind to the *Tnp1* promoter in mice. JHDM2A removes the repressive H3K9me2/1 methylation marks, thereby facilitating the transcriptional activation of *Tnp1* and *Prm1* [18]. This epigenetic control is a key upstream regulatory step, linking histone methylation status to the activation of the histone-to-protamine transition. The promoter also contains binding sites for other spermatid-specific transcription factors, and its activity is modulated by the chromatin remodeling machinery. ### 1.4 Enhancer Elements and Long-Range Regulation While the proximal promoter is sufficient for basal and cell-type-specific expression, full and robust expression of *TNP1* likely requires the action of distal enhancer elements. Comparative genomics studies have identified conserved non-coding sequences in the vicinity of the spermatid-expressed genes *Odf1*, *Prm1*, *Prm2*, *Tnp1*, and *Tnp2* [19]. These conserved regions are hypothesized to function as enhancers or matrix attachment regions that coordinate the high-level, synchronous expression of these genes during the post-meiotic phase of spermatogenesis. The precise three-dimensional chromatin architecture that brings these enhancers into proximity with the *TNP1* promoter remains an active area of investigation. ### 1.5 Isoforms and Transcript Variants The *TNP1* gene is intronless, and consequently, it does not undergo alternative splicing to generate multiple protein isoforms. The primary transcript is essentially the mature mRNA. The 5' and 3' untranslated regions (UTRs) are relatively short. However, the 3' UTR contains regulatory elements that are targets for microRNAs (miRNAs). In bovine, functional SNPs within the *TNP1* 3' UTR have been identified in the target sites for **bta-miR-532** and **bta-miR-204**. These SNPs are significantly associated with semen quality traits, indicating that post-transcriptional regulation by miRNAs is a crucial layer of control over TNP1 expression [20]. This miRNA-mediated regulation allows for the fine-tuning of TNP1 protein levels, ensuring that chromatin condensation proceeds at the correct rate and timing. --- ## 2. 3D Protein Domain Architecture & Structural Biology ### 2.1 Primary Sequence and Physicochemical Properties The TNP1 protein is a small, arginine- and lysine-rich polypeptide of 73 amino acids in humans. Its primary sequence is characterized by an extremely high content of basic residues, which gives the protein a very high isoelectric point (pI > 12). This strong positive charge is fundamental to its function, enabling it to bind electrostatically to the negatively charged phosphate backbone of DNA. The protein lacks a classical globular fold and is classified as an intrinsically disordered protein (IDP) in its free state. This intrinsic disorder is a common feature of linker histones and protamines, allowing for promiscuous and adaptable binding to DNA. ### 2.2 Domain Architecture Despite its small size, the TNP1 protein can be conceptually divided into distinct functional domains: - **N-Terminal Domain (Residues 1–~20):** This region is rich in basic amino acids and is thought to be the primary DNA-binding domain. It contains clusters of arginine and lysine residues that can interact with the major and minor grooves of DNA. - **Central Domain (Residues ~21–~50):** This region contains a highly conserved sequence motif that is the hallmark of the TNP1 protein. It includes a series of serine and threonine residues that are substrates for post-translational phosphorylation. The central domain is also involved in protein-protein interactions, particularly with other chromatin-associated proteins. - **C-Terminal Domain (Residues ~51–73):** The C-terminus is also basic and contributes to DNA binding. It may also play a role in the recognition and displacement of histone proteins from the DNA. The C-terminal region contains a conserved tryptophan residue that has been used in biophysical studies to monitor the protein's interaction with DNA. ### 2.3 Secondary and Tertiary Structure Circular dichroism (CD) spectroscopy and nuclear magnetic resonance (NMR) studies have shown that TNP1 is largely unstructured in solution. However, upon binding to DNA, it undergoes a disorder-to-order transition, adopting a more defined conformation. The protein is believed to bind along the minor groove of DNA, with its basic residues neutralizing the phosphate backbone. The central domain may form a short alpha-helix or extended structure upon DNA binding, facilitating the compaction of the DNA helix. The overall architecture is that of a "protein bridge" that can bring distant regions of the DNA strand into close proximity, promoting chromatin condensation. ### 2.4 Post-Translational Modifications and Structural Dynamics The most significant post-translational modification of TNP1 is **phosphorylation**. The protein is transiently phosphorylated on multiple serine and threonine residues during the early stages of spermiogenesis. This phosphorylation is critical for the proper function of TNP1. It is hypothesized that phosphorylation reduces the overall positive charge of the protein, weakening its initial binding to DNA and allowing it to "scan" for the correct binding sites. Subsequent dephosphorylation increases the protein's positive charge, locking it into a high-affinity binding state and driving chromatin condensation. This phosphorylation-dephosphorylation cycle is a dynamic regulatory mechanism that controls the timing and extent of chromatin compaction. ### 2.5 Interactive 3D Visualizer To explore the three-dimensional structure and surface charge distribution of the TNP1 protein, an interactive visualizer is available. This tool allows for the manipulation of the protein model, highlighting key residues and domains. `[Interactive 3D Protein Visualizer: Load TNP1 (PDB: true)](/tools/protein-structure-viewer?source=alphafold&accession=P09430)` --- ## 3. Cellular Signaling Pathways & Molecular Function ### 3.1 The Histone-to-Protamine Transition The primary molecular function of TNP1 is to mediate the **histone-to-protamine transition** during spermiogenesis. This is a dramatic chromatin remodeling event that occurs in elongating spermatids, where the vast majority of histones are removed and replaced by protamines, resulting in a highly compact, transcriptionally inert sperm nucleus. The process can be broken down into several key steps: 1. **Histone Hyperacetylation:** Prior to histone removal, the core histones (particularly H4) undergo extensive acetylation. This acetylation neutralizes the positive charge on the histone tails, weakening their interaction with DNA and destabilizing the nucleosome structure. 2. **Histone Displacement:** The hyperacetylated, destabilized histones are then displaced from the DNA. This process is facilitated by transition proteins, including TNP1 and TNP2, which enter the chromatin and bind to the DNA. 3. **Chromatin Condensation:** TNP1 and TNP2 bind to the DNA, neutralizing its negative charge and causing the DNA to collapse into a more condensed state. The binding of TNP1 is thought to be particularly important for the initial compaction of the DNA. 4. **Protamine Deposition:** Following the action of transition proteins, the protamines (PRM1 and PRM2) are synthesized and replace the transition proteins. Protamines are even more basic than transition proteins and contain multiple cysteine residues that form disulfide bonds, creating a highly stable, interlocking network that locks the DNA into its final, hypercondensed state. ### 3.2 Regulation of TNP1 Expression The expression of *TNP1* is governed by a complex interplay of hormonal, paracrine, and autocrine signals. - **Endocrine and Paracrine Signaling:** The **androgen-binding protein (ABP)**, secreted by Sertoli cells, has been shown to stimulate *Tnp1* gene expression in spermatids *in vitro* [1, 21]. This suggests that ABP, by concentrating androgens in the seminiferous tubule, plays a direct role in promoting the expression of this key chromatin remodeling gene. - **Transcriptional Control:** As discussed in Section 1.3, the transcription factor **CREM** is the primary driver of *TNP1* expression. The activity of CREM is itself regulated by the **FSH/cAMP/PKA signaling pathway**. FSH binds to its receptor on Sertoli cells, activating adenylyl cyclase and increasing cAMP levels. This, in turn, activates PKA, which phosphorylates and activates CREM. The **JHDM2A** histone demethylase is also essential for *Tnp1* transcription, as it removes repressive histone methylation marks from the promoter [18]. - **Post-Transcriptional Control:** The translation of *TNP1* mRNA is also regulated. The mRNA is stored in a translationally repressed state in round spermatids and is only translated in elongating spermatids. This translational delay is controlled by RNA-binding proteins that interact with elements in the 3' UTR. Additionally, as noted earlier, miRNAs such as bta-miR-532 and bta-miR-204 can bind to the 3' UTR and negatively regulate TNP1 expression [20]. ### 3.3 Protein-Protein Interaction Networks TNP1 does not act in isolation. It interacts with a network of proteins to execute its function. - **Histones:** TNP1 directly interacts with core histones, facilitating their displacement from DNA. - **TNP2:** TNP1 and TNP2 are co-expressed and likely cooperate in chromatin condensation. Studies in double-knockout mice (*Tnp1*⁻/⁻; *Tnp2*⁻/⁻) show a more severe phenotype than either single knockout, indicating functional redundancy and cooperation [2]. - **Protamines:** TNP1 must be removed from the DNA to allow for protamine deposition. The mechanism of this exchange is not fully understood but likely involves the competition between TNP1 and protamines for DNA binding sites. - **Chromatin Remodeling Factors:** TNP1 may interact with other chromatin remodeling complexes that facilitate the removal of histones and the incorporation of transition proteins. ### 3.4 Signaling Pathway Diagram The following Mermaid diagram illustrates the key signaling pathways and molecular events leading to TNP1 function. ```mermaid flowchart TD A["FSH"] --> B["Sertoli Cell"] B --> C["cAMP/PKA"] C --> D["CREM Activation"] D --> E["TNP1 Gene Transcription"] F["Testosterone"] --> G["ABP"] G --> H["Spermatid"] H --> I["TNP1 mRNA Translation"] E --> I I --> J["TNP1 Protein"] J --> K["Histone Displacement"] K --> L["Chromatin Condensation"] L --> M["Protamine Deposition"] M --> N["Mature Sperm Nucleus"] O["JHDM2A"] --> E ``` --- ## 4. Pathogenic Hotspot Mutations & Clinical Differentials ### 4.1 TNP1 and Male Infertility Given its critical role in spermiogenesis, it is not surprising that mutations and polymorphisms in the *TNP1* gene are associated with male infertility. The clinical spectrum ranges from azoospermia (no sperm in the ejaculate) to oligozoospermia (low sperm count) and teratozoospermia (abnormal sperm morphology). ### 4.2 Specific Mutations and Polymorphisms - **Haplotype - GCG:** A specific haplotype in the *TNP1* gene, designated "- GCG", has been significantly associated with azoospermia in Indian men [4]. This haplotype likely affects the promoter or regulatory regions, leading to reduced gene expression. - **Missense and Nonsense Mutations:** Mutation analysis in infertile men with varicocele has identified several mutations in the *TNP1* gene [2]. These include missense mutations that alter the amino acid sequence, potentially disrupting the protein's DNA-binding ability or its phosphorylation sites. Nonsense mutations that introduce a premature stop codon would result in a truncated, non-functional protein. - **Single-Nucleotide Polymorphisms (SNPs):** Numerous SNPs have been identified in the *TNP1* gene across different populations. A study comparing fertile and infertile Japanese men found several SNPs, some of which were more prevalent in the infertile group [3]. A meta-analysis of gene polymorphisms and male infertility concluded that while individual SNPs may have small effects, combinations of SNPs in genes like *TNP1*, *PRM1*, and *PRM2* can contribute significantly to infertility risk [4, 5]. - **SNPs in miRNA Target Sites:** As mentioned earlier, SNPs in the 3' UTR of *TNP1* that fall within miRNA target sites can affect gene expression. In Chinese Holstein bulls, these SNPs were associated with semen quality traits, demonstrating the functional importance of these non-coding variants [20]. ### 4.3 Functional Consequences of Mutations The functional consequences of *TNP1* mutations are primarily related to defects in chromatin condensation. - **Abnormal Chromatin Structure:** Mutations that reduce TNP1 expression or function lead to incomplete histone removal and abnormal chromatin condensation. This results in sperm with less compact nuclei and increased DNA susceptibility to damage. - **Increased DNA Fragmentation:** Studies have shown that altered *TNP1* expression is correlated with high sperm DNA fragmentation [3]. This DNA damage can impair fertilization and embryo development. - **Reduced Fertilization Potential:** Sperm with abnormal chromatin structure have a reduced capacity to fertilize an oocyte. TNP1 has been proposed as a novel biomarker for fertilization failure in patients undergoing ICSI [9]. ### 4.4 TNP1 in Non-Reproductive Pathologies While primarily a testis-specific gene, aberrant expression of *TNP1* has been observed in certain cancers. This is part of a phenomenon known as **cancer/testis (CT) antigen expression**, where genes normally restricted to the testis are ectopically activated in tumors. - **Breast Cancer:** A study investigating the "TNP1 non-gene region" found that low-risk alleles in this region influence tumor characteristics in breast cancer [6]. This suggests that genetic variation in or near the *TNP1* locus may modulate cancer risk or progression. - **Testicular Germ Cell Tumours (TGCT):** *TNP1* has been identified as one of the differentially expressed genes in TGCT, and it may serve as a potential prognostic biomarker [7]. - **Esophageal Squamous Cell Carcinoma (ESCC):** A DNA damage repair gene-related prognostic model for ESCC included *TNP1* as one of the key genes, linking its expression to the tumor microenvironment and patient prognosis [8]. ### 4.5 Clinical Differentials When a patient presents with infertility, the clinical differential diagnosis is broad. The presence of *TNP1* mutations should be considered in cases of: - **Non-obstructive azoospermia (NOA):** Particularly when testicular biopsy reveals spermatogenic arrest at the round or elongating spermatid stage [5, 16]. - **Severe oligozoospermia or teratozoospermia:** When standard semen analysis reveals a high percentage of sperm with abnormal head morphology, which can be indicative of defective chromatin condensation. - **Unexplained fertilization failure:** In couples undergoing assisted reproductive technologies (ART), where sperm parameters appear normal but fertilization repeatedly fails [9]. --- ## 5. Host-Pathogen & Viral Interactions (If applicable) The interaction of the TNP1 protein with pathogens is not a primary aspect of its biology, given its highly restricted expression in male germ cells. However, there are intriguing, albeit indirect, connections. ### 5.1 The Agrobacterium tumefaciens 6b Oncoprotein A notable example of a pathogen protein interacting with a TNP1 homolog comes from plant biology. The oncoprotein **6b** from *Agrobacterium tumefaciens* has been shown to interact with a tobacco nucleolar protein that is homologous to TNP1 [9]. This tobacco protein is encoded by a transposable element of *Antirrhinum majus* and shares sequence similarity with the mammalian TNP1. This interaction suggests that the 6b oncoprotein may hijack the host's chromatin remodeling machinery to alter gene expression and promote tumor formation in plants. While this is not a direct interaction with the human TNP1, it highlights the conserved nature of these basic nuclear proteins and their potential as targets for pathogen effectors. ### 5.2 Viral Impact on Spermatogenesis Several viral infections are known to impair male fertility, often by causing orchitis (inflammation of the testis) or by directly affecting spermatogenic cells. While no virus is known to directly target the TNP1 protein, viral infections can indirectly disrupt its expression and function: - **Inflammation and Oxidative Stress:** Viral infections can induce a strong inflammatory response in the testis, leading to the production of reactive oxygen species (ROS). This oxidative stress can damage sperm DNA and proteins, including TNP1, and can also disrupt the hormonal milieu required for normal spermatogenesis. - **Epigenetic Dysregulation:** Some viruses can integrate into the host genome or alter the host's epigenetic landscape. This could potentially affect the expression of developmentally regulated genes like *TNP1*, although this has not been specifically demonstrated. ### 5.3 Environmental Toxicants and TNP1 Exposure to environmental toxicants has been shown to affect *TNP1* expression, acting as a "pathogen-like" stressor. - **Microplastics:** A study on the effects of microplastics in drinking water found that exposure altered sperm parameters and the expression of *TNP1* and *TNP2* genes [10]. - **Ionizing Radiation:** Occupational exposure to ionizing radiation in radiology workers was linked to male reproductive impairment, including changes in sperm nuclear protein gene expression [11]. - **Tobacco Smoke and Nicotine:** Smoking has a well-documented negative impact on male fertility. Studies have shown that tobacco smoke and nicotine downregulate the expression of *TNP1* and other sperm nuclear protein genes, leading to increased DNA fragmentation and reduced sperm quality [12, 13]. - **Leptin:** High levels of leptin, often associated with obesity, have been shown to adversely affect the histone-to-protamine transition, likely by disrupting the expression of *Tnp1* and other key genes [14, 15]. --- ## 6. Pharmacogenomics, Drug Targets & Small-Molecule Inhibitors ### 6.1 TNP1 as a Drug Target TNP1 is not a conventional drug target in the sense of an enzyme or receptor that can be easily modulated by small molecules. Its function is primarily structural, and it is an intrinsically disordered protein. However, there are several contexts in which TNP1 could be considered a target for therapeutic intervention. ### 6.2 Male Contraception The specific and essential role of TNP1 in spermatogenesis makes it a potential target for the development of a non-hormonal male contraceptive. The goal would be to transiently inhibit TNP1 function, leading to a reversible block in sperm chromatin condensation and the production of non-functional spermatozoa. Potential strategies include: - **Small-Molecule Inhibitors:** Identifying small molecules that bind to TNP1 and prevent its interaction with DNA or histones. This is challenging due to the protein's intrinsic disorder, but not impossible. - **Antisense Oligonucleotides (ASOs) or siRNA:** Delivering ASOs or siRNAs that specifically target *TNP1* mRNA to the testis could knock down its expression. This approach has been explored for other testis-specific genes. - **Peptide Aptamers:** Designing peptide aptamers that mimic the DNA-binding domain of TNP1 could competitively inhibit its function. ### 6.3 Cancer Therapy The aberrant expression of *TNP1* in certain cancers (as a cancer/testis antigen) makes it an attractive target for immunotherapy. - **Cancer Vaccines:** Peptides derived from TNP1 could be used to create a therapeutic cancer vaccine that stimulates the patient's immune system to attack TNP1-expressing tumor cells. - **Adoptive Cell Transfer (ACT):** T cells engineered to express a T-cell receptor (TCR) specific for a TNP1-derived peptide presented on MHC molecules could be used for ACT therapy. ### 6.4 Fertility Treatment In the context of male infertility, the goal is not to inhibit TNP1 but to restore its normal function. This is not a pharmacogenomic intervention in the traditional sense, but rather a diagnostic and prognostic one. - **Biomarker for ART:** Measuring *TNP1* mRNA levels in sperm or seminal fluid can serve as a biomarker for sperm quality and fertilization potential [9, 16]. This can help guide clinical decisions regarding the choice of ART (e.g., ICSI vs. IVF). - **Gene Therapy:** In the future, gene therapy could be used to correct mutations in the *TNP1* gene in spermatogonial stem cells. This is a highly experimental approach but represents a potential long-term cure for certain forms of genetic male infertility. ### 6.5 Current Status Currently, there are no FDA-approved drugs that specifically target TNP1. All potential therapeutic applications are in the research and development phase. The primary clinical utility of TNP1 at present is as a diagnostic and prognostic biomarker for male infertility. --- ## 7. Bioinformatic Resources & Database Accessions The following table provides key database accessions and resources for the TNP1 gene and protein. | **Database** | **Identifier / Accession** | **Description** | | :--- | :--- | :--- | | **NCBI Gene** | 7141 | Primary gene record for human *TNP1*. | | **Ensembl** | ENSG00000118271 | Ensembl gene ID for human *TNP1*. | | **UniProtKB** | P09430 | Primary protein sequence and annotation record. | | **RCSB PDB** | N/A (No experimental structure) | Structural models may be available via homology modeling (e.g., AlphaFold). | | **HGNC** | 11948 | HUGO Gene Nomenclature Committee entry. | | **OMIM** | 190231 | Online Mendelian Inheritance in Man entry. | | **GeneCards** | GC02M073400 | Comprehensive gene and protein information. | | **STRING** | 9606.ENSP00000238454 | Protein-protein interaction networks. | | **BioGRID** | 112583 | Biological General Repository for Interaction Datasets. | | **Gene Ontology (GO)** | GO:0003677 (DNA binding); GO:0006334 (nucleosome assembly); GO:0007286 (spermatid development) | Functional annotations. | | **ClinVar** | Varies by variant | Clinical significance of specific genetic variants. | --- ## Related Clinical & Scientific Guides * [PMCH Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/developmental-biology/pmch-gene-structure-function-pathway) * [CYLC1 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/developmental-biology/cylc1-gene-structure-function-pathway) * [CRX Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/developmental-biology/crx-gene-structure-function-pathway) ## References [1] K. 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