pFusionRed-f-mem is a mammalian expression vector intended for red fluorescent labeling of plasma membrane in living cells. The vector encodes red fluorescent protein FusionRed (see reporter description) targeted to plasma membrane by 20 amino acid farnesylation signal from c-Ha-Ras [Aronheim et al., 1994; Hancock et al., 1991]. The farnesylation signal is fused to the FusionRed C-terminus.

FusionRed codon usage is optimized for high expression in mammalian cells (humanized) [Haas et al., 1996]. To increase mRNA translation efficiency, Kozak consensus translation initiation site is generated upstream of the FusionRed-f-mem coding sequence [Kozak, 1987].

pFusionRed-f-mem vector can be used as a source of FusionRed-f-mem hybrid sequence. The vector backbone contains unique restriction sites that permit its excision and further insertion into expression vector of choice.

Note: The plasmid DNA was isolated from dam⁺-methylated E. coli. Therefore some restriction sites are blocked by methylation. If you wish to digest the vector using such sites you will need to transform the vector into a dam^- host and make fresh DNA.

The vector backbone contains immediate early promoter of cytomegalovirus (P_{CMV IE}) for protein expression, SV40 origin for replication in mammalian cells expressing SV40 T-antigen, pUC origin of replication for propagation in E. coli, and f1 origin for single-stranded DNA production. SV40 polyadenylation signals (SV40 poly A) direct proper processing of the 3'-end of the reporter mRNA.

SV40 early promoter (P_SV40) provides neomycin resistance gene (Neo^r) expression to select stably transfected eukaryotic cells using G418. Bacterial promoter (P) provides kanamycin resistance gene expression (Kan^r) in E. coli. Kan^r/Neo^r gene is linked with herpes simplex virus (HSV) thymidine kinase (TK) polyadenylation signals.

pFusionRed-f-mem vector can be transfected into mammalian cells by any known transfection method. CMV promoter provides strong, constitutive expression of the FusionRed-f-mem in eukaryotic cells. If required, stable transformants can be selected using G418 [Gorman, 1985].

Suitable host strains for propagation in E. coli include DH5alpha, HB101, XL1-Blue, and other general purpose strains. Plasmid incompatibility group is pMB1/ColE1. The vector confers resistance to kanamycin (30 μg/ml) to E. coli hosts. Copy number in E. coli is about 500.

Two African green monkey kidney fibroblast cells expressing FusionRed targeted to plasma membrane by 20-amino acid farnesylation signal from c-Ha-Ras.