Table 1.

Analysis of junctions in inversion-type class-switch substrate

Clone	Sμ Junction			Sα junction			Homology
	Upstream end (a)	Downstream end (e)	Duplication/ deletion	Upstream end (d)	Downstream end (b)	Duplication/ deletion	Upstream junction (c)	Downstream junction (f)
SCR2(μ,α)
101	189	520	−330 ≈−320	533	539	−5 ≈5	5	5
102	189	1029	−839 ≈−825	299	533	−233 ≈−219	0	14
105	520	682	−161 ≈−150	586	548	39 ≈50	2	9
106	175	189	−13 ≈−10	135	154	−18 ≈−15	1	2
107	88	89	0 ≈3	833	841	−7 ≈−4	3	0
108	374	905	−530 ≈−526	336	347	−10 ≈−6	2	2
109	490	532	−41 ≈−26	292	329	−36 ≈−21	1	14
110	584	1102	−517 ≈−513	610	666	−55 ≈−51	2	2
111	583	945	−361 ≈−355	1028	1037	−8 ≈−2	6	0
114	516	530	−13	371	386	−14	0	0
115	309	356	−46 ≈−35	40	42	−1 ≈10	0	11
116	309	356	−46 ≈−24	40	52	−11 ≈11	11	11
117	652	663	−10 ≈0	365	367	−1 ≈9	9	1
118	934	947	−12 ≈7	598	611	−12 ≈7	7	12
119	145	696	−550 ≈−539	779	792	−12 ≈−1	0	11
120	299	395	−95 ≈−84	336	354	−17 ≈−6	9	2
121	408	443	−34 ≈−21	98	757	−658 ≈−645	8	5
122	719	730	−10 ≈−5	504	521	−16 ≈−11	2	3
123	500	507	−6 ≈2	898	925	−26 ≈−18	0	8
125	442	181	262 ≈266	403	421	−17 ≈−13	4	0
126	919	954	−34 ≈−19	277	318	−40 ≈−25	13	2
SCR2(μ,Rα)
205	129	136	−6 ≈−1	249	260	−10 ≈−5	1	4
207	357	360	−2	386	378	9	0	0
209	973	976	−2	26	59	−32	0	0
210	973	975	−1 ≈0	24	54	−29 ≈−28	0	1
211	416	422	−5 ≈−4	348	588	−239 ≈−238	1	0
212	402	520	−117	215	260	−44	0	0
213	777	795	−17 ≈−14	254	257	−2 ≈1	0	3
214	887	888	0 ≈1	25	48	−22 ≈−21	0	1
215	755	756	0 ≈4	38	59	−20 ≈−16	0	4
216	751	772	−20	163	186	−22	0	0
217	181	189	−7 ≈−3	536	555	−18 ≈−14	4	0
218	71	90	−18	215	233	−17	0	0
219	492	415	78 ≈79	683	837	−153 ≈−152	0	1
220	889	916	−26 ≈−21	58	83	−24 ≈−19	1	4
222	151	166	−14 ≈−11	459	466	−6 ≈−3	1	2
229	683	705	−21 ≈−19	292	317	−24 ≈−22	1	1
230	172	447	−274 ≈−272	405	414	−8 ≈−6	2	0
233	256	974	−717 ≈−713	24	283	−258 ≈−254	3	1
235	50	938	−887 ≈−886	264	768	−503 ≈−502	1	0
236	760	752	9	37	64	−26	0	0

A summary of 82 junctions from 41 postswitch clones derived from SCR2(μ,α) and SCR2(μ,Rα) transfectants is shown. Listed are nucleotide positions of upstream (a) and downstream (e) ends (Fig. 2) of Sμ junction relative to the promoter-proximal end of the S region. Ranges of duplication or deletion are shown, which were calculated from a and e, taking the length of junctional homology (c and f) into account. The plus and minus values indicate duplication and deletion, respectively. Similar analyses for Sα junctions (d and b) are shown also. Unequivocal cases for duplication are typed in bold.