Recombinant DNA technology has a major advantage in that it is capable of producing specific therapeutic proteins on demand in a heterologous expression system. The extent of this notion can be understood when one considers how crucial such proteins are, and how problematic the economical and safe production of such proteins are. Therapeutic recombinant protein production is a fundamental aspect of 21st century biotechnology industries. The improved therapeutic recombinant protein expression systems that use prokaryotic and eukaryotic cells have enabled the development of a multi‐billion dollar industry. Among the variety of available heterologous expression systems, the baculovirus‐based insect cell expression system has been utilized frequently for the high‐level production of therapeutic recombinant proteins. Thus, the baculovirus expression system has been recognized as one of the most powerful expression technologies for production, by virtue of the achievable amount and purity, and the ease of the eukaryotic production process. The majority of therapeutic proteins are glycoproteins originating from humans. The insect‐based expression system harbors glycosylation processing pathways, which constitute an advantage over other prokaryotic systems that lack glycosylation. However, there are several drawbacks which must be circumvented in order to establish an efficient system for the production of recombinant proteins. This review presents a brief overview of the perspective, particularly the glycosylation aspect, of the production of therapeutic recombinant proteins via a baculovirus‐based insect cell expression system.

No abstract

No abstract

Baculovirus has been widely used for the production of numerous recombinant proteins in insect cells. Baculovirus vectors have several advantages, including proper post-translational modification, biosafety, and multiple large gene expression ability. Most insect cell-produced proteins have been expressed by using the baculovirus expression vector system (BEVS) under the control of strong polyhedrin (Polh) or p10 promoters. There has been no report on the expression of recombinant proteins by baculovirus in plant cells. In this study, we used the baculovirus vector to express recombinant green fluorescent protein (GFP) in plants. To investigate the expression of GFP protein by baculovirus in plants, we cloned the gfp gene under the control of Polh promoter or Cauliflower Mosaic Virus (CaMV) 35S promoter to yield the Polh-GFP and 35S-GFP bacmids carrying the GFP expression cassettes, respectively. The presence of Polh-GFP and 35S-GFP expression cassettes in the bacmids was confirmed by polymerase chain reaction (PCR). Subsequently, both the GFP bacmids and GFP baculovirus vectors generated from the bacmid-transfected Sf9 insect cells were inoculated into Nicotiana benthamiana leaves. Confocal microscopy revealed that the gfp gene expression was high in plant leaves at 48 and 72 h after bacmid and baculovirus inoculation. Reverse transcription-PCR (RT-PCR) and fluorescence microscopy confirmed that the gfp genes under the control of Polh or CaMV35S promoters were highly expressed in plant leaves inoculated with 40 L of baculovirus solution. These results suggested that the baculovirus vector can be used to express recombinant proteins in plants. The baculovirus vector-mediated gene delivery and expression system could be used in plant biotechnology for fast and efficient production of recombinant proteins and for molecular virology studies in plants.Additional key words: CaMV 35S promoter, GFP protein, Sf9 insect cell, polyhedrin promoter Hort. Environ. Biotechnol. 52(1):95-104. 2011.