Table 29.3: Small nuclear ribonucleoprotein particles (snRNPs) in the splicing of mRNA precursors

snRNP	Size of snRNA (nucleotides)	Role
U1	165	Binds the 5′ splice site
U2	185	Binds the branch site and forms part of the catalytic center
U5	116	Binds the 5′ splice site and then the 3′ splice site
U4	145	Masks the catalytic activity of U6
U6	106	Catalyzes splicing