pEBFP-N1 carries a blue fluorescent variant of the Aequorea victoria green fluorescent protein gene (GFP). The EBFP gene contains four amino acid substitutions. The Tyr-66 to His substitution gives EBFP fluorescence excitation and emission maxima (380 and 440 nm, respectively) similar to other blue emission variants (1–3). The other three substitutions (Phe-64 to Leu; Ser-65 to Thr; and Tyr- 145 to Phe) enhance the brightness and solubility of the protein, primarily due to improved proteinfolding properties and efficiency of chromophore formation (1, 4, 5). The Em of EBFP is 31,000 cm–1M–1 for 380-nm excitation, leading to a fluorescent signal that is 2–3-fold brighter than other blue variants of GFP and roughly equivalent to wt GFP. In addition, the rate of photobleaching of EBFP is one-half to one-third that of P4-3, a popular predecessor to EBFP (1). EBFP contains >190 silent mutations that create an open reading frame comprised almost entirely of preferred human codons (6). Furthermore, upstream sequences flanking EBFP have been converted to a Kozak consensus translation initiation site (7). These changes increase the translational efficiency of the EBFP mRNA and consequently the expression of EBFP in mammalian and plant cells.

The MCS in pEBFP-N1 is between the immediate early promoter of CMV (PCMV IE) and the EBFP coding sequences. Genes cloned into the MCS will be expressed as fusions to the N-terminus of EBFP if they are in the same reading frame as EBFP and there are no intervening stop codons. The inserted gene should include an initiating ATG codon. EBFP with N-terminal fusion moieties retain the fluorescent properties of the native protein and thus can be used to localize fusion proteins in vivo.

The vector contains an SV40 origin for replication and a neomycin resistance (Neor ) gene for selection (using G418) in mammalian cells. A bacterial promoter upstream of this cassette (P) expresses kanamycin resistance in E. coli. The vector backbone also provides a pUC19 origin of replication for propagation in E. coli and an f1 origin for single-stranded DNA production.

0001 TAGTTATTAA TAGTAATCAA TTACGGGGTC ATTAGTTCAT AGCCCATATA TGGAGTTCCG 
0061 CGTTACATAA CTTACGGTAA ATGGCCCGCC TGGCTGACCG CCCAACGACC CCCGCCCATT 
0121 GACGTCAATA ATGACGTATG TTCCCATAGT AACGCCAATA GGGACTTTCC ATTGACGTCA 
0181 ATGGGTGGAG TATTTACGGT AAACTGCCCA CTTGGCAGTA CATCAAGTGT ATCATATGCC 
0241 AAGTACGCCC CCTATTGACG TCAATGACGG TAAATGGCCC GCCTGGCATT ATGCCCAGTA 
0301 CATGACCTTA TGGGACTTTC CTACTTGGCA GTACATCTAC GTATTAGTCA TCGCTATTAC 
0361 CATGGTGATG CGGTTTTGGC AGTACATCAA TGGGCGTGGA TAGCGGTTTG ACTCACGGGG 
0421 ATTTCCAAGT CTCCACCCCA TTGACGTCAA TGGGAGTTTG TTTTGGCACC AAAATCAACG 
0481 GGACTTTCCA AAATGTCGTA ACAACTCCGC CCCATTGACG CAAATGGGCG GTAGGCGTGT 
0541 ACGGTGGGAG GTCTATATAA GCAGAGCTGG TTTAGTGAAC CGTCAGATCC GCTAGCGCTA 
0601 CCGGACTCAG ATCTCGAGCT CAAGCTTCGA ATTCTGCAGT CGACGGTACC GCGGGCCCGG 
0661 GATCCACCGG TCGCCACCAT GGTGAGCAAG GGCGAGGAGC TGTTCACCGG GGTGGTGCCC 
0721 ATCCTGGTCG AGCTGGACGG CGACGTAAAC GGCCACAAGT TCAGCGTGTC CGGCGAGGGC 
0781 GAGGGCGATG CCACCTACGG CAAGCTGACC CTGAAGTTCA TCTGCACCAC CGGCAAGCTG 
0841 CCCGTGCCCT GGCCCACCCT CGTGACCACC CTGACCTACG GCGTGCAGTG CTTCAGCCGC 
0901 TACCCCGACC ACATGAAGCA GCACGACTTC TTCAAGTCCG CCATGCCCGA AGGCTACGTC 
0961 CAGGAGCGCA CCATCTTCTT CAAGGACGAC GGCAACTACA AGACCCGCGC CGAGGTGAAG 
1021 TTCGAGGGCG ACACCCTGGT GAACCGCATC GAGCTGAAGG GCATCGACTT CAAGGAGGAC 
1081 GGCAACATCC TGGGGCACAA GCTGGAGTAC AACTACAACA GCCACAACGT CTATATCATG 
1141 GCCGACAAGC AGAAGAACGG CATCAAGGTG AACTTCAAGA TCCGCCACAA CATCGAGGAC 
1201 GGCAGCGTGC AGCTCGCCGA CCACTACCAG CAGAACACCC CCATCGGCGA CGGCCCCGTG 
1261 CTGCTGCCCG ACAACCACTA CCTGAGCACC CAGTCCGCCC TGAGCAAAGA CCCCAACGAG 
1321 AAGCGCGATC ACATGGTCCT GCTGGAGTTC GTGACCGCCG CCGGGATCAC TCTCGGCATG 
1381 GACGAGCTGT ACAAGTAAAG CGGCCGCGAC TCTAGATCAT AATCAGCCAT ACCACATTTG 
1441 TAGAGGTTTT ACTTGCTTTA AAAAACCTCC CACACCTCCC CCTGAACCTG AAACATAAAA 
1501 TGAATGCAAT TGTTGTTGTT AACTTGTTTA TTGCAGCTTA TAATGGTTAC AAATAAAGCA 
1561 ATAGCATCAC AAATTTCACA AATAAAGCAT TTTTTTCACT GCATTCTAGT TGTGGTTTGT 
1621 CCAAACTCAT CAATGTATCT TAAGGCGTAA ATTGTAAGCG TTAATATTTT GTTAAAATTC 
1681 GCGTTAAATT TTTGTTAAAT CAGCTCATTT TTTAACCAAT AGGCCGAAAT CGGCAAAATC 
1741 CCTTATAAAT CAAAAGAATA GACCGAGATA GGGTTGAGTG TTGTTCCAGT TTGGAACAAG 
1801 AGTCCACTAT TAAAGAACGT GGACTCCAAC GTCAAAGGGC GAAAAACCGT CTATCAGGGC 
1861 GATGGCCCAC TACGTGAACC ATCACCCTAA TCAAGTTTTT TGGGGTCGAG GTGCCGTAAA 
1921 GCACTAAATC GGAACCCTAA AGGGAGCCCC CGATTTAGAG CTTGACGGGG AAAGCCGGCG 
1981 AACGTGGCGA GAAAGGAAGG GAAGAAAGCG AAAGGAGCGG GCGCTAGGGC GCTGGCAAGT 
2041 GTAGCGGTCA CGCTGCGCGT AACCACCACA CCCGCCGCGC TTAATGCGCC GCTACAGGGC 
2101 GCGTCAGGTG GCACTTTTCG GGGAAATGTG CGCGGAACCC CTATTTGTTT ATTTTTCTAA 
2161 ATACATTCAA ATATGTATCC GCTCATGAGA CAATAACCCT GATAAATGCT TCAATAATAT 
2221 TGAAAAAGGA AGAGTCCTGA GGCGGAAAGA ACCAGCTGTG GAATGTGTGT CAGTTAGGGT 
2281 GTGGAAAGTC CCCAGGCTCC CCAGCAGGCA GAAGTATGCA AAGCATGCAT CTCAATTAGT 
2341 CAGCAACCAG GTGTGGAAAG TCCCCAGGCT CCCCAGCAGG CAGAAGTATG CAAAGCATGC 
2401 ATCTCAATTA GTCAGCAACC ATAGTCCCGC CCCTAACTCC GCCCATCCCG CCCCTAACTC 
2461 CGCCCAGTTC CGCCCATTCT CCGCCCCATG GCTGACTAAT TTTTTTTATT TATGCAGAGG 
2521 CCGAGGCCGC CTCGGCCTCT GAGCTATTCC AGAAGTAGTG AGGAGGCTTT TTTGGAGGCC 
2581 TAGGCTTTTG CAAAGATCGA TCAAGAGACA GGATGAGGAT CGTTTCGCAT GATTGAACAA 
2641 GATGGATTGC ACGCAGGTTC TCCGGCCGCT TGGGTGGAGA GGCTATTCGG CTATGACTGG 
2701 GCACAACAGA CAATCGGCTG CTCTGATGCC GCCGTGTTCC GGCTGTCAGC GCAGGGGCGC 
2761 CCGGTTCTTT TTGTCAAGAC CGACCTGTCC GGTGCCCTGA ATGAACTGCA AGACGAGGCA 
2821 GCGCGGCTAT CGTGGCTGGC CACGACGGGC GTTCCTTGCG CAGCTGTGCT CGACGTTGTC 
2881 ACTGAAGCGG GAAGGGACTG GCTGCTATTG GGCGAAGTGC CGGGGCAGGA TCTCCTGTCA 
2941 TCTCACCTTG CTCCTGCCGA GAAAGTATCC ATCATGGCTG ATGCAATGCG GCGGCTGCAT 
3001 ACGCTTGATC CGGCTACCTG CCCATTCGAC CACCAAGCGA AACATCGCAT CGAGCGAGCA 
3061 CGTACTCGGA TGGAAGCCGG TCTTGTCGAT CAGGATGATC TGGACGAAGA GCATCAGGGG 
3121 CTCGCGCCAG CCGAACTGTT CGCCAGGCTC AAGGCGAGCA TGCCCGACGG CGAGGATCTC 
3181 GTCGTGACCC ATGGCGATGC CTGCTTGCCG AATATCATGG TGGAAAATGG CCGCTTTTCT 
3241 GGATTCATCG ACTGTGGCCG GCTGGGTGTG GCGGACCGCT ATCAGGACAT AGCGTTGGCT 
3301 ACCCGTGATA TTGCTGAAGA GCTTGGCGGC GAATGGGCTG ACCGCTTCCT CGTGCTTTAC 
3361 GGTATCGCCG CTCCCGATTC GCAGCGCATC GCCTTCTATC GCCTTCTTGA CGAGTTCTTC 
3421 TGAGCGGGAC TCTGGGGTTC GAAATGACCG ACCAAGCGAC GCCCAACCTG CCATCACGAG 
3481 ATTTCGATTC CACCGCCGCC TTCTATGAAA GGTTGGGCTT CGGAATCGTT TTCCGGGACG 
3541 CCGGCTGGAT GATCCTCCAG CGCGGGGATC TCATGCTGGA GTTCTTCGCC CACCCTAGGG 
3601 GGAGGCTAAC TGAAACACGG AAGGAGACAA TACCGGAAGG AACCCGCGCT ATGACGGCAA 
3661 TAAAAAGACA GAATAAAACG CACGGTGTTG GGTCGTTTGT TCATAAACGC GGGGTTCGGT 
3721 CCCAGGGCTG GCACTCTGTC GATACCCCAC CGAGACCCCA TTGGGGCCAA TACGCCCGCG 
3781 TTTCTTCCTT TTCCCCACCC CACCCCCCAA GTTCGGGTGA AGGCCCAGGG CTCGCAGCCA 
3841 ACGTCGGGGC GGCAGGCCCT GCCATAGCCT CAGGTTACTC ATATATACTT TAGATTGATT 
3901 TAAAACTTCA TTTTTAATTT AAAAGGATCT AGGTGAAGAT CCTTTTTGAT AATCTCATGA 
3961 CCAAAATCCC TTAACGTGAG TTTTCGTTCC ACTGAGCGTC AGACCCCGTA GAAAAGATCA 
4021 AAGGATCTTC TTGAGATCCT TTTTTTCTGC GCGTAATCTG CTGCTTGCAA ACAAAAAAAC 
4081 CACCGCTACC AGCGGTGGTT TGTTTGCCGG ATCAAGAGCT ACCAACTCTT TTTCCGAAGG 
4141 TAACTGGCTT CAGCAGAGCG CAGATACCAA ATACTGTCCT TCTAGTGTAG CCGTAGTTAG 
4201 GCCACCACTT CAAGAACTCT GTAGCACCGC CTACATACCT CGCTCTGCTA ATCCTGTTAC 
4261 CAGTGGCTGC TGCCAGTGGC GATAAGTCGT GTCTTACCGG GTTGGACTCA AGACGATAGT 
4321 TACCGGATAA GGCGCAGCGG TCGGGCTGAA CGGGGGGTTC GTGCACACAG CCCAGCTTGG 
4381 AGCGAACGAC CTACACCGAA CTGAGATACC TACAGCGTGA GCTATGAGAA AGCGCCACGC 
4441 TTCCCGAAGG GAGAAAGGCG GACAGGTATC CGGTAAGCGG CAGGGTCGGA ACAGGAGAGC 
4501 GCACGAGGGA GCTTCCAGGG GGAAACGCCT GGTATCTTTA TAGTCCTGTC GGGTTTCGCC 
4561 ACCTCTGACT TGAGCGTCGA TTTTTGTGAT GCTCGTCAGG GGGGCGGAGC CTATGGAAAA 
4621 ACGCCAGCAA CGCGGCCTTT TTACGGTTCC TGGCCTTTTG CTGGCCTTTT GCTCACATGT 
4681 TCTTTCCTGC GTTATCCCCT GATTCTGTGG ATAACCGTAT TACCGCCATG CAT