What type of RNA does eukaryotic RNA polymerase III mainly transcribe?

Eukaryotic RNA polymerase III is primarily responsible for transcribing a variety of small RNA molecules essential for protein synthesis and other cellular functions. Among these, the most notable is transfer RNA (tRNA), which plays a crucial role in translation by helping to decode mRNA into polypeptides.

Additionally, RNA polymerase III also transcribes other small nuclear RNAs (snRNA), which are involved in RNA splicing, and some types of small cytoplasmic RNAs. However, tRNA is one of the most significant products of RNA polymerase III transcription because of its direct involvement in the translation process.

In contrast, mRNA is mainly transcribed by RNA polymerase II, which is responsible for synthesizing messenger RNAs that carry the genetic information from DNA to the ribosome for protein synthesis. The other RNA types mentioned, such as pRNA, do not play as central a role in translation as tRNA does.

Overall, the primary role of eukaryotic RNA polymerase III in producing tRNA highlights its importance in the overall process of gene expression and protein synthesis in eukaryotic cells.