PCR analysis for verification of presence of mini-F sequences in CPXV.BR, vBRf or vBR. DNA isolated from cells infected with CPXV.BR, vBRf or vBR was subjected to PCR targeting TK and the mini-F vector. Lanes 1 and 2 contain PCR amplicons using primer pairs #237+#265 or #264+#240, respectively, which target full-length TK. Bands at sizes of 1,126 bp or 1,054 bp, respectively, are obtained in the case that mini-F sequences are absent in the DNA analyzed. Lanes 3 and 4 using primer pairs #264+#238 or #239+#265) only yield a PCR product in the case that the mini-F sequence is still present and result in bands of 324 bp and 210 bp, respectively. Gel images for the individual virus DNAs are shown and the size of a molecular weight marker (generuler 1-kb plus DNA ladder, Fermentas) are given.