### POLD3 Gene Overview

**Gene Symbol:** POLD3

**Function:**  
POLD3 encodes the 66-kDa accessory subunit of DNA polymerase delta, which is crucial for DNA replication and repair. The protein has a significant role in enhancing the activity of DNA polymerase delta by stabilizing its structure and facilitating its interaction with other subunits and cofactors like proliferating cell nuclear antigen (PCNA). POLD3 primarily participates in high-fidelity DNA synthesis, especially in lagging strand formation and in various DNA repair mechanisms, including nucleotide excision repair (NER) and translesion synthesis (TLS).

### 1. Associated Genes
POLD3 is associated with several other genes, particularly those that encode key components of the DNA replication and repair machinery, including:

- **POLD1**: the catalytic subunit of DNA polymerase delta.
- **PCNA**: a processivity factor that enhances the polymerase activity.
- **RFC1**: a member of the replication factor C complex that helps load PCNA onto DNA.
- **POLD2**: another auxiliary subunit of the DNA polymerase delta complex.

Additionally, genes involved in DNA damage response and repair processes, such as those coding for DNA repair enzymes, may also be indirectly associated.

### 2. Aging and Age-related Diseases
While specific research directly linking POLD3 to aging is limited, the gene's involvement in DNA replication and repair is crucial in the context of aging and age-related diseases. Impairment in DNA repair mechanisms, often due to dysregulation of DNA polymerases like POLD3, can lead to genomic instability, contributing to cancer development and other age-associated degenerative conditions. 

Studies have suggested that mutations or alterations in polymerase functions could accelerate aging processes or increase susceptibility to age-related diseases, such as neurodegenerative disorders. Additionally, as DNA repair efficiency declines with age, the role of POLD3 could become increasingly vital in maintaining genomic integrity.

### 3. Drug Interactions
Currently, there are no specific drugs universally recognized to directly interact with the POLD3 gene or its protein product. However, drugs that modulate DNA replication and repair processes in general may indirectly affect the way POLD3 operates. This includes certain chemotherapeutics or agents that induce DNA damage, which may require DNA polymerase delta for repair.

Several classes of drugs potentially influencing DNA repair mechanisms, and those might indirectly relate to the function of POLD3, include:

- **Antineoplastic agents**: These include drugs that can induce DNA damage (e.g., cisplatin).
- **DNA damage response inhibitors**: These drugs could aim to inhibit specific kinases involved in the DNA damage signaling pathway, thus indirectly affecting POLD3 function.

### 4. Pathways and Biological Processes
POLD3 is involved in several biological processes and signaling pathways, including:

- **DNA Replication**: Integral in synthesizing new DNA strands during replication.
- **DNA Repair**:
  - **Nucleotide Excision Repair**: Facilitating repair mechanisms for bulky DNA lesions caused by UV light.
  - **Translesion Synthesis**: Allowing DNA replication past DNA lesions or damage, thereby maintaining replication fork integrity under stress conditions.
- **Repair of Broken Replication Forks**: Assists in break-induced replication (BIR) that occurs when replication forks are damaged.
- **Cell Cycle Regulation**: Participates in DNA synthesis during the S-phase, crucial for cell division.

These pathways illustrate the essential role of POLD3 in maintaining genomic stability and integrity, which is critical for preventing mutations that can lead to cancer and other diseases.