Figure 1.

Schematic diagram of NDV-D90 and recombinant NDV-GFP cDNA clone construction. (A) Four cDNA fragments, marked by F1, F2, F3 and F4, were generated by RT-PCR from NDV D90 genomic RNA. These cDNA fragments were sequentially cloned and assembled into a modified pBR322 vector using In-Fusion^® PCR cloning kit (Clontech, USA). (B) The open reading frame of the EGFP gene was cloned into the intergenic region between the P and M genes in the D90 full-length clone as an additional transcription unit. The NDV Gene Start and Gene End signal sequences and the EGFP sequences are boxed or underlined.