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Fig. 1. Illustration of the linker-GFP construct with the location of the consensus
myristoylation sequence and the positions where the mutations were introduced
(A), expression of the recombinant proteins in COS-7 cells (B) and fatty
acylation of the GFP chimeras (C). By recursive PCR, the triplet AGS repeated
nine times was created following a consensus N-myristoylation sequence and
fused in frame to the GFP sequence. Mutations were introduced at Gly2, Cys3,
Ser9, Ser15 and Ser21 in various combinations, as described in the Materials
and Methods (A). The different linker-GFP constructs were inserted in a pCDNA3
vector that was used to transfect COS-7 cells (B). Transfected COS-7 cells
were starved for 1 hour in DMEM without serum and were then metabolically
labeled for 4 hours with either [3H]-myristic acid (Myr) or
[3H]-palmitic acid (Palm). Cell lysates were immunoprecipitated
with an anti-GFP antibody, analyzed by SDS-PAGE and exposed to a film as
described in the Materials and Methods. Identical results were obtained in two
independent metabolic labeling experiments.