FIGURE 6.

Maturation of U6 snRNA. Following transcription by Pol III, La protein protects the U6 snRNA precursor by binding the four uridines at the 3′ end. La protein is later replaced by TENT1, which uridylates the U6 snRNA 3′ end. The 3′‐5′ exoribonuclease and phosphodiesterase USB1 removes uridines, leaving only five of them, and a terminal 2′,3′ cyclic phosphate (2′3′ > P). The U6 snRNA is further protected by recruitment of the Lsm2‐8 protein complex. The blue dot at the 5′ end represents the γ‐monomethylguanosine triphosphate (meGTP) cap