5-Bromo-UTP (5-BrUTP) trisodium is a derivative of uridine triphosphate (UTP). 5-Bromo-UTP trisodium can be utilized by cells as a precursor for RNA synthesis. During transcription, it integrates into the newly synthesized RNA chain and replaces some UTP. 5-Bromo-UTP trisodium can be used to label newly synthesized RNA, thereby enabling high-resolution visualization of transcriptional sites and RNA transport[1][2].