The RDXP3 gene, also referred to as "retinoid X receptor, beta," plays a role in gene expression regulation and cellular processes. Here’s an overview of the gene with respect to your requests:

### 1. Associated Genes:
While specific genes directly associated with RDXP3 are not widely documented in the available summaries from NCBI and UniProt, the following genes may be functionally or regulatory connected based on shared pathways or interactions:
- **RXRα (retinoid X receptor alpha)**: A key partner in forming heterodimers with other nuclear receptors.
- **PPARγ (peroxisome proliferator-activated receptor gamma)**: Often interacts with RXR in lipid metabolism regulation.
- More broadly, genes involved in retinoic acid signaling, such as **RARA** (retinoic acid receptor, alpha) may also be considered in the context of RDXP3 due to related pathways.

### 2. Aging and Age-Related Diseases:
RDXP3 may be implicated in aging and age-related diseases through its interactions with signaling pathways that regulate metabolism and cellular stress responses. While no direct studies are explicitly focused on RDXP3 in the context of aging are specified, retinoid signaling plays critical roles in cell differentiation, immune response, and possibly neurodegenerative processes. Dysregulation of retinoid signaling has been linked to:
- Neurodegenerative diseases
- Cardiovascular diseases
- Metabolic syndromes

### 3. Drug Interactions:
Drugs that may interact with RDXP3 are typically those that act on retinoid signaling pathways or nuclear receptors. Some potential drug classes include:
- **Retinoids**: These are derivatives of vitamin A and are used in treatments for acne and some forms of cancer. Drugs such as isotretinoin and tretinoin may have interactions due to their mechanism of action.
- **Thiazolidinediones**: Drugs like rosiglitazone and pioglitazone, which act on PPARγ (and may interact with RXR).

### 4. Pathways and Biological Processes:
RDXP3 is involved in several key biological processes and pathways:
- **Retinoid signaling pathway**: Governs the regulation of gene expression in response to retinoids (vitamin A derivatives).
- **Regulation of lipid metabolism**: Through interaction with nuclear receptors involved in metabolic processes.
- **Cell differentiation**: Plays a role in the differentiation of various cell types, particularly in immune and epithelial tissues.
- **Cell cycle regulation**: Can participate in the control of the cell cycle, ultimately influencing growth and proliferation.

In conclusion, RDXP3 is an important gene connected to several pathways and biological processes potentially linked to aging and disease states. Its interactions with drugs, particularly those acting on retinoic pathways, further highlights its relevance in both therapeutic and physiological contexts. More precise associations and studies would be required to elucidate its functions thoroughly.