EXPRESSION OF CHIMERIC gag GENES FROM HUMAN IMMUNODEFICIENCY VIRUS IN TOMATO (Lycopersicon esculentum Mill.) AND Escherichia coli

Abstract

Native sequence of gag gene from human immunodeficienvy virus (HIV) was used to express in tomato (Lycopersicon esculentum Mill.) plants and also in E. coli. Two versions of chimeric gag gene (gag-ENV y gag-RT) were expressed independently. According to the expression analysis the messenger RNA from chimeric versions of gag gene was detected in tomato leaves and fruit tissues. However, we did not detect expression of the whole Gag protein in tomato plants, although the antibody did detect the p24 capsid domain expression in two transformed lines of Gag-ENV. During HIV expression in mammalian cells the late genes such as gag promote instability of viral RNA messengers, and this could also be happening in plant tissues. Gag itself is able to originate viral-like particles (VLPs) of HIV when is expressed in heterologous systems, such as E. coli and yeast. In this report, Gag-RT and Gag-ENV constructs were expressed in E. coli to confirm if chimeric proteins Gag-RT and Gag-ENV are able to assembly into viral like particles. Expression of these constructs yielded moderate levels in E. coli (2 mg L^-1 of Gag-RT and 4 mg L^-1 of Gag-ENV) of purified chimeric proteins. Electron microscopy studies showed the presence of viral-like particles in cytoplasm of E. coli cells expressing Gag-ENV protein, thus indicating that addition of the epitopes did not interfere with proper assembly of Gag in bacterial cells.