Table 1.

Signature sequences and modifications of major snRNAs. The 5′ cap and 3′ nucleosides, base modified nucleosides, and alkali resistant oligonucleotides were determined by many methods described in the text. The table provides a summary of individual RNA characteristics of rat Novikoff hepatoma cells.

RNA	Subspecies	Localization	5′ End	3′ End	Modified Nucleotides
4.5S RNA	I	Extranucleolar nuclei	pppG	U-OH
	II (U6)	Extranucleolar nuclei	mpppG	U-OH	3Ψ, m6A, m2G, AmA, AmG, AmGmC, CmC, CmA, CmCmU
	III	Extranucleolar nuclei	pA	Um	AmA, GmA, 2GmG, m2G, m6A, 3Ψ
5S RNA	I	Nucleoli, nuclei and cytoplasm	pppG	U-OH
	II	Nucleoli, nuclei and cytoplasm	pppG	U-OH
	III (U5)	Extranucleolar nuclei	m3 2,2,7GpppAmUmAC	U-OH A-OH	UmU, GmC, 2Ψ
U1 RNA	U1a (5.8S RNA)	Nucleoli and cytoplasm	pC, pG	U-OH	UmG, GmC, Ψ
	U1b, U1c	Extranucleolar nuclei	m3 2,2,7GpppAmUmAC	U-OH, G-OH	AmC, 2Ψ
U2 RNA		Extranucleolar nuclei	m3 2,2,7GpppAmUmC	C-OH A-OH	GmGmC, GmG, GmA, m6AmG, CmΨ, UmA, CmU, 13Ψ, (m6A, m2G)
U3 RNA	U3a, U3b, U3c, U3d	Nucleoli	m3 2,2,7GpppAmA(m)AG	A-OH, U-OH, C-OH	2Ψ