To construct the cDNA for rhMPV/GFP, a NheI-N/P-GFP-NheI cassette was constructed with the N/P noncoding region (NCR) upstream of the GFP gene. An NheI site was introduced into the hMPV SphI/ClaI subclone at nt 5474, located at the stop codon of M2-2, using the primer 5'GCTTACTTAAGCTAGCTAAAAACACATCAGAGTGG (NheI site underlined) and its complement. Following NheI digestion, the NheI-N/P-GFP-NheI cassette was ligated into the subclone. A StuI (nt4495) to ClaI (nt8693) fragment, containing M2, GFP, SH and G genes, was isolated from the hMPV SphI/ClaI subclone and inserted into the full-length cDNA to form rhMPV/GFP.