Table 1

Number of U dimers that can form on UV irradiation

VirusLeaderMaximum no. of U dimers
I-60 I-108
3′Internal3′Internal
Dec-U3118
WT61482014
Inc-U8168
  • The maximum number of covalent U dimers that could form on UV irradiation are shown. For I-60 and I-108 the values are shown for initiation of synthesis at the 3′ end (3′) or for initiation of synthesis directly at the first gene start site (Internal). Sequences are shown in Fig. 1A and Materials and Methods. To calculate the number of U dimers we used the following assumptions: U3 can only form 1, U4 and U5 can form a maximum of 2, and U6 and U7 can form a maximum of 3.