 This gene is represented in the transcriptome (287).
Ac34: ac34, unknown function
The gene ac43 encodes a hypothetical protein of 24.9 kDa (215 aa) with a conserved domain with unknown function according to the CDD database (176). Homologs are found in all Alphabaculoviruses except Spodoptera litura (Splt) NPV (Table 2).
Ac35: v-ubi, viral ubiquitin
The gene v-ubi encodes the viral ubiquitin (V-UBI) protein (8.7 kDa, 77 aa). The protein has 70% identity to eukaryotic ubiquitin proteins and is produced at maximal levels between 14 and 18 h p.i., indicating that the gene is a late gene (82). The gene has been classified as an auxiliary gene and the encoded ubiquitin is likely involved in signaling the degradation of proteins by the 26S proteome (197). Homologs are present in all Alpha-and Betabaculoviruses except Leucania separate (Ls)NPV (Table 2 and Table 3).
Ac36: 39K/pp31, nuclear matrix associated phosp-hoprotein
The gene pp31 (also known as 39K) encodes a phosphoprotein (31.3 kDa, 112 aa) that can bind in a non-specific way to ssDNA and dsDNA with equal affinity and is essential for late gene expression, i.e. it serves as a late expression factor (22, 86). In addition, a pp31-null mutant was prepared of AcMNPV, and microarray and quantitative PCR showed that pp31 is not essential for viral DNA replication. However, the deletion resulted in a minor down-regulation of a subset of both early and late genes and, as for BmNPV (77), in decreased BV production (287).
Ac37: lef-11, late expression factor 11
Lef-11 codes for the late expression factor-11 (LEF-11) with a calculated mass of 13.1 kDa (112 aa). Its messenger RNA is present from 3 to 36 h p.i., while LEF-11 is detected until 72 h p.i. and localizes within a dense region of infected nuclei (158). LEF-11 is not essential for DNA replication in transient replication assays (169), but is necessary for the activity of late gene promoters (262). An AcMNPV lef-11 null mutant was not able to replicate in Sf9 cells and late gene transcription was absent (157).
Ac38: ac38, ADP-ribose pyrophosphatase
The Ac38 protein (25.3 kDa, 216 aa) has homology with proteins in the Nudix (nucleotide diphosphate X) superfamily of pyrophosphatases and contains the conserved Nudix motif: GX5EX7REUXEEX2U (U: I, L or V, and X: any amino acid). Within this superfamily, the Ac38 protein shows the closest phylogenetic relationship with ADP-ribose pyrophosphatases (ADPRases). Recombinant Ac38 indeed has in vitro ADPRase activity (70). Transcripts of ac38 are detectable from 2 h p.i. and the level increases during the late stage of infection. Deletion of ac38 decreases the yield of BV to less than 1% of the wild type virus (70). So far, the gene is conserved in all Alpha-and Betabaculoviruses (Table 2 and Table 3).
Ac39: p43, ODV protein of unknown function
The 43.5 kDa protein P43 (363 aa) encoded by the gene ac39, is present in the proteome of ODVs (20). No putative conserved domains have been detected and its function other than being an ODV protein is still enigmatic. Homologs are present in seven NPV genomes.
Ac40: p47, transcription regulator
The ac40 gene product has a molecular mass of 47.5 kDa (P47;401 aa) and belongs to the group of factors required for late gene expression (262). Moreover, the gene p47 together with three other genes ac50, ac62 and ac90 -coding for lef-8, lef-9 and lef-4, respectively -form a RNA polymerase complex that transcribes late and very late viral genes (88), while early genes are transcribed by the host RNA polymerase Ⅱ (106). P47 directly binds to all other subunits of the late viral RNA complex, as well as to itself, and P47 is required for the association of LEF-4 with LEF-8 (44). Ac40 is a baculovirus core gene.
Ac41: lef-12, late expression factor 12
Ac41 encodes late expression factor 12, LEF-12 (21.1 kDa, 181 aa), which stimulates late gene expression in transient assays in a cell type specific manner (167). In a virus context, lef-12 is neither essential for virus replication nor for expression of late genes, but it has a stimulatory affect on late ge