FIG. 6.

M2 (VP1 RNA) expression levels in cells transfected with VP231-SRα or AVP231-SRα. To test potential roles of the agnoprotein and its coding sequence in expression of M2, COS-7 cells were transfected with VP231-SRα or AVP231-SRα, and total RNA was extracted from the transfected cells. Total RNA was first diluted 1:10 and then serially diluted twofold (1:10 to 1:2,560). The RNA was analyzed by RT-PCR with the primer pair V1-VAS3; then the products from M2 (706 bp) were semiquantitatively compared. M2 expression from VP231-SRα-transfected cells was slightly higher than that from AVP231-SRα-transfected cells. This small difference in M2 expression levels was roughly within twofold. The same RNA recovery was demonstrated by analyzing SV40 large T antigen RNA as an internal control for COS-7 cells.