Table 1. Distribution of unpaired bases within the siRNA targeted structures.

The table reports the number of observations (siRNAs) targeting mRNA regions with a variable number of unpaired bases. A single siRNA can target more than one local secondary structure within the mRNA. Only few siRNAs (both VH and L) bind to mRNA regions with higher amounts of unpaired nts.

	Loop 5′		Loop 3′		Int-loop		mb-Loop		H-loop		b-Loop		One-bb		Stem
Unpaired bases	VH	L	VH	L	VH	L	VH	L	VH	L	VH	L	VH	L	VH	L
Number of observations (siRNAs)
0	94	91	102	111	82	88	83	95	114	118	127	135	99	106	90	89
1	7	18	2	10	1	–	22	18	–	–	1	–	38	41	28	33
2	8	13	10	10	21	17	15	17	–	–	7	3	5	2	15	19
3	8	10	13	5	13	11	9	5	3	6	5	3	–	–	6	2
4	5	5	6	7	7	9	6	4	4	6	2	4	–	–	4	5
5	8	4	4	2	6	10	2	4	13	12	1	2	–	–	–	–
6	5	–	1	–	4	5	1	1	22	2	–	1	–	–	–	1
7	–	–	–	–	–	–	–	–	3	3	–	–	–	–	–	–
8	–	–	–	–	–	–	–	–	2	–	–	–	–	–	–	–
9	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–
10	–	1	1	1	–	2	–	–	–	–	–	–	–	–	–	–
11	–	2	–	–	–	1	–	–	–	–	–	–	–	–	–	–
12	–	–	–	–	–	–	1	–	–	–	–	–	–	–	–	–
13	1	–	–	–	1	–	–	–	–	–	–	–	–	–	–	–
14	1	–	1	–	–	–	–	–	1	–	–	–	–	–	–	–
15	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–
16	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–
17	–	–	1	–	–	–	–	–	–	–	–	–	–	–	–	–
18	–	–	–	1	–	–	–	–	–	–	–	–	–	–	–	–