This invention discloses a
nucleic acid molecule encoding a modified retroviral Gag
protein and its applications. The Gag
protein contains an engineered acylated tag sequence at its N-terminus, comprising: a
glycine residue at the second position after the initiating
methionine for myristylation modification; and / or a
cysteine residue in the N-terminal region for palmitoylation modification. The tag sequence is selected from SEQ ID NO:1, 3-9, or derivative
amino acid sequences having at least 80% identity and retaining function. Preferably, the modification involves replacing the first 9 amino acids at the N-terminus of the wild-type HIV-1 Gag
protein with the aforementioned tag to enhance membrane anchoring and improve viral packaging efficiency. This invention also provides packaging plasmids containing this molecule, host cells, packaging systems, and preparation methods. This invention can significantly improve viral yield and
titer, and is particularly suitable for overcoming the efficiency
bottleneck in packaging large-load lentiviruses of 7-10 kb.