### TSEN15 Gene Overview
The TSEN15 gene encodes a non-catalytic subunit of the tRNA splicing endonuclease complex, which plays a critical role in the process of tRNA maturation by removing introns from pre-tRNA molecules. This endonuclease activity is essential for the proper functioning of tRNA, which is crucial for protein synthesis. Additionally, TSEN15 has been implicated in multiple RNA processing events, including pre-mRNA 3'-end formation. 

### 1. Associated Genes
While the initial summaries are limited in listing specific associated genes, it’s known that the tRNA splicing endonuclease complex involves several other subunits. The endonuclease complex comprises three other non-catalytic subunits: TSEN54 (another endonuclease), TSEN32, and TSEN34, which work collectively to execute the tRNA splicing function. Mutations or dysregulation in these associated TSEN genes may lead to similar functional impairments concerning tRNA processing.

### 2. Aging and Age-related Diseases
Research has identified that defects in tRNA splicing endonuclease components like TSEN15 can lead to a range of disorders, including neurodegenerative diseases such as pontocerebellar hypoplasia (PCH). PCH is often characterized by developmental delays and neurological problems as well as brain abnormalities. Moreover, certain deficiencies in tRNA processing have been implicated in age-related diseases due to the accumulation of faulty or incomplete proteins leading to cellular stress and degeneration, although specific mechanisms linking TSEN15 to aging are still being elucidated.

### 3. Drug Interactions
Currently, there is no specific drug linked directly to TSEN15 gene function or its product. However, since TSEN15 is part of the broader RNA processing pathways, potential therapeutic strategies that target RNA processing might indirectly affect the functions of TSEN15. Moreover, ongoing research into translation and tRNA-related therapies may yield relevant pharmacological agents in the future.

### 4. Pathways and Biological Processes
The TSEN15 gene is primarily associated with the following pathways and biological processes:
- **tRNA Processing:** It is directly involved in the splicing of tRNA, where it identifies and cleaves the intron regions to facilitate the maturation of tRNA molecules.
- **mRNA Processing:** TSEN15 is also implicated in the regulation of mRNA 3'-end processing, linking tRNA splicing to mRNA modifications.
- **Nuclear RNA Processing:** Additionally, it contributes to the broader category of RNA metabolism occurring in the nucleus.

In terms of Gene Ontology (GO) terms, TSEN15 gene is likely annotated with functions linked to nucleic acid binding, endonuclease activity, and regulatory roles in RNA splicing. Further research may reveal additional biological processes and pathways directly influenced by TSEN15.