Table 3.

Nucleotide composition of the transcripts with HeLa nuclear extract in the presence of cytidine analogues

Reaction	Number of nucleotides nearest to GMP
	Ap	Gp	Cp	Up	C*p
Urxn	22.7 ± 1.5	20.6 ± 0.4	19.9 ± 0.2	17.8 ± 1.6
ho4Crxn	25.1 ± 1.5	20.2 ± 0.8	18.3 ± 2.0	14.5 ± 1.4	2.9 ± 0.2
mo4Crxn	25.4 ± 1.6	19.0 ± 0.4	16.3 ± 2.3	17.4 ± 1.4	2.9 ± 0.8
rPrxn	27.8 ± 0.3	19.4 ± 1.6	18.5 ± 1.2	5.6 ± 0.1	9.7 ± 0.7
sc4Crxn	29.4 ± 1.7	16.8 ± 1.1	5.9 ± 1.1	19.3 ± 1.4	9.5 ± 0.2
rP/1/5/Urxn	29.0 ± 2.8	18.9 ± 0.4	18.9 ± 0.7	12.0 ± 1.6	1.8 ± 0.2
sc4C/1/5Crxn	28.0 ± 1.3	18.7 ± 0.7	17.3 ± 0.7	15.7 ± 1.3	1.3 ± 0.1

In the control reaction (Urxn), ATP, CTP, ³²P-GTP and UTP at the molar ratio of 1:1:0.2:1 were added to the extract. In ho⁴Crxn, mo⁴Crxn, and rPrxn, the CTP analogues, ho⁴CTP, mo⁴CTP and rPTP, respectively, were added in place of UTP, while sc⁴CTP was added in place of CTP. In P/1/5/Urxn and sc⁴C/1/5Crxn, molar ratios of ATP, CTP, GTP, UTP and rPTP and sc⁴CTP were 1:1:0.2:0.2:1 and 1:0.2:0.2:1, respectively. The numbers of nucleotides 5′ to G were determined via the following equation: (radioactivity of each nucleotide)/(total radioactivity of all nucleotides) × [81 (total numbers of nucleotides at 5′ neighbor of G)]. The theoretical numbers of nucleotides are Ap = 25, Gp = 21, Cp = 23 and Up = 12.