In order to address this deficiency, in this work, a construction of recombinant baculovirus containing multigene expression cassettes was made using the MultiBac system as described . Here, we chose to use the unmodified subunits, rather than any tagged proteins that could result in the assembly of complexes which might have modified or compromised properties. The detailed logic of adding subunits is shown in Figure 1 in which a recombinant transfer vector pFBDM- containing four gene expression cassettes was generated. Due to the multiplication module between the two DAPT promoters, the pFBDM is particularly suited for generating multigene expression cassettes, making the generation of recombinant forms of pol d containing mutations in any one of the subunits or different subunit combinations thereof extremely easy. Our previous studies indicated that the fourth subunit p12 was not a passive structural element for the stability of pol d, but that its interaction with the core dimer produced alterations in the conformation and/or structure of the catalytic site that are essential for the catalytic properties of the pol d holoenzyme . Pol d itself may be a target of the DNA damage response. As genotoxic agents and replication stress triggered the degradation of the p12 subunit, pol d was converted to a trimeric form, whose altered responses to encounters with DNA lesions might contribute to the DNA damage response . In order to provide a foundation for assessing the contributions of p12 and p68 on the functions of the catalytic core enzyme consisting of p125 and p50, a rigorous analysis of the enzymatic behavior of pol d and its subassemblies will be needed. Therefore, by the use of a similar strategy, we also constructed the recombinant transfer vectors, pFBDM- for pol d core, two trimers, pFBDM- and pFBDM- lacking p68 or p12, respectively. Since Maeda et al. first reported the production of human a-interferon in CP-690550 silkworm using recombinant BmNPV , silkworm larvae have been used as a bioreactor for the production of huge recombinant proteins for decades. Recently a novel Bacto- Bac system using BmNPV is established by the construction of BmNPV bacmid DNA with a miniF replicon , kanamycin-resistant gene, lacZ gene, mini-attachment Tn7 site , which possesses a comparable time saving, high performance and high efficiency to Bac-to-Bac baculovirus expression system using AcMNPV distributed from Invitrogen Corp.