Figure 1.

Boundaries of the HPV-16 NRE. The 5′ deletion series described earlier (6) was complemented by a 3′ deletion series. Effects on NRE activity were assayed using CAT reporter constructs with different NRE portions present upstream of the HPV-16 late poly(A) site. CAT activities relative to plasmid C-SE227 (100%) are indicated. ▴, 3′ deletion series; , 5′ deletion series; ♦, point mutations in 5′ splice site homologies 1 (m5′ss1) or 3 and 4 (m5′ss3+4).