POLRMT, also known as mitochondrial RNA polymerase, is essential for the transcription of the mitochondrial genome. It plays a crucial role in mitochondrial biogenesis and functions related to the electron transport chain (ETC) as the mitochondrial genome encodes essential ETC proteins [2]. It is also involved in mitochondrial DNA replication, as demonstrated by the complete mtDNA loss when either TFB2M or POLRMT is knocked out in cultured human cybrid cells, indicating its importance in the priming of both strand-asynchronous and strand-coupled replication [6].

Mutations in POLRMT can lead to neurological diseases. Patients with POLRMT variants present with global developmental delay, hypotonia, short stature, and speech/intellectual disability in childhood, and one subject had progressive external ophthalmoplegia. Patient fibroblasts have a defect in mitochondrial mRNA synthesis. In vitro studies of recombinant POLRMT mutants show deleterious effects on mitochondrial transcription [1]. Additionally, targeting POLRMT has shown potential in cancer treatment. Inhibitors like IMT1 can disrupt mitochondrial functions in various cancer cells such as colorectal, prostate, and osteosarcoma cells, leading to decreased cell viability, proliferation, and migration, and inducing apoptosis. Genetic depletion of POLRMT also has similar effects, highlighting its importance in cancer cell growth [3,4,5].

In conclusion, POLRMT is vital for mitochondrial transcription and replication. Studies using loss-of-function models, such as gene knockout in cells, have revealed its role in neurological diseases and cancer. Targeting POLRMT could be a promising strategy for treating certain cancers, and understanding its function is crucial for uncovering disease mechanisms in both neurological and cancer-related conditions.