RNA polymerase 2 (RNA Polymerase II) is the enzyme responsible for synthesizing messenger RNA in eukaryotes, comprising 12 subunits with a complex structure. Located primarily in the nucleus, it carries out the central process of gene transcription. RNA polymerase 2 interacts with transcription factors and regulatory proteins, participating in intricate transcription regulation and signaling pathways. Its gene expression varies across different tissues and developmental stages, with mutations potentially leading to transcription errors, associated with various diseases such as cancer and genetic disorders.