White Spot Syndrome Virus Immediate-early Gene Research Articles

The immediate early protein WSV187 can influence viral replication via regulation of JAK/STAT pathway in Drosophila

The world production of shrimp is seriously affected by the white spot syndrome virus (WSSV). Viral immediate-early (IE) genes encode regulatory proteins critical for the viral lifecycle. In spite of their importance, only five out of the 21 identified WSSV IE genes are functionally characterized. Here, we report the use of Drosophila melanogaster as a model to explore the role of WSSV IE gene wsv187. In vivo expression of WSV187 in transgenic flies show WSV187 localized in the cytoplasm. Overexpression of wsv187 results wing defects consistent with phenotypes observed in JAK/STAT exacerbated flies. After artificial infection of the DCV virus, the flies expressing wsv187 showed a lower viral load, a higher survival rate and an up-regulated STAT92E expression. These data demonstrate wsv187 plays a role in the controlling of virus replication by activating host JAK/STAT pathway.

Characterization of white spot syndrome virus immediate-early gene promoters

Twenty-one immediate-early (IE) genes of white spot syndrome virus (WSSV) have been identified so far. However, the transcriptional regulation of WSSV IE genes remains largely unknown. In this report, the 5' flanking regions of 18 WSSV IE genes were cloned and eight functional promoter regions were identified. WSSV IE gene promoters normally contained a TATA box approximately 30 bp upstream of the transcriptional initiation site. Also, the cyclic AMP response element (CRE; TGACGTCA) was frequently found within the WSSV IE promoter regions. Mutations of the CREs of WSSV IE promoters P403 and P465 reduced their activity significantly, suggesting that these elements have a role in WSSV IE gene transcription. Our findings provide a more global view of WSSV IE gene promoters and will facilitate the in-depth investigation of viral gene transcriptional regulation.

Identification of the immediate-early genes of white spot syndrome virus

During viral infection, viral immediate-early (IE) genes encode regulatory proteins critical for the viral life cycle. Here we screened white spot syndrome virus (WSSV) IE genes with cycloheximide (CHX)-treated primary culture of crayfish hemocyte and a WSSV genome tiling microarray. Sixteen ORFs, including a known WSSV IE gene ( ie1/ wsv069), were identified and confirmed by RT-PCR and time course studies. The 16 identified IE proteins contain four proteins ( wsv051, wsv069, wsv100, wsv079) with transcription activity, one ( wsv083) with Ser/Thr kinase domain and one ( wsv249) previously described to function as an ubiquitin E3 ligase. Furthermore, most of the identified WSSV IE genes cluster in a 14 kb genomic region (WSSV China isolate: 36,052 to 50,300 bp). This type of arrangement may facilitate the coordinate control and rapid expression of IE genes.