Comment on

• Use of green fluorescent protein variants to monitor gene transfer and expression in mammalian cells.

  Cheng L, Fu J, Tsukamoto A, Hawley RG. Cheng L, et al. Nat Biotechnol. 1996 May;14(5):606-9. doi: 10.1038/nbt0596-606. Nat Biotechnol. 1996. PMID: 9630951
• Retroviral transfer and expression of a humanized, red-shifted green fluorescent protein gene into human tumor cells.

  Levy JP, Muldoon RR, Zolotukhin S, Link CJ Jr. Levy JP, et al. Nat Biotechnol. 1996 May;14(5):610-4. doi: 10.1038/nbt0596-610. Nat Biotechnol. 1996. PMID: 9630952