Duck Plague Virus pUL48 Protein Activates the Immediate-Early Gene to Initiate the Transcription of the Virus Gene

Tong Zhou; Dengjian Fan; Mingshu Wang; Anchun Cheng; Ying Wu; Qiao Yang; Bin Tian; Renyong Jia; Xumin Ou; Sai Mao; Di Sun; Shaqiu Zhang; Dekang Zhu; Shun Chen; Mafeng Liu; Xin-Xin Zhao; Juan Huang; Qun Gao; Yanling Yu; Ling Zhang

doi:10.3389/fmicb.2021.795730

Duck Plague Virus pUL48 Protein Activates the Immediate-Early Gene to Initiate the Transcription of the Virus Gene

Front Microbiol. 2021 Dec 23:12:795730. doi: 10.3389/fmicb.2021.795730. eCollection 2021.

Authors

Tong Zhou^{1

2

3}, Dengjian Fan^{1

2

3}, Mingshu Wang^{1

2

3}, Anchun Cheng^{1

2

3}, Ying Wu^{1

2

3}, Qiao Yang^{1

2

3}, Bin Tian^{1

2

3}, Renyong Jia^{1

2

3}, Xumin Ou^{1

2

3}, Sai Mao^{1

2

3}, Di Sun^{1

2

3}, Shaqiu Zhang^{1

2

3}, Dekang Zhu^{2

3}, Shun Chen^{1

2

3}, Mafeng Liu^{1

2

3}, Xin-Xin Zhao^{1

2

3}, Juan Huang^{1

2

3}, Qun Gao^{1

2

3}, Yanling Yu^{1

2

3}, Ling Zhang^{1

2

3}

Affiliations

¹ Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.
² Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.
³ Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.

Abstract

Duck plague caused by the duck plague virus (DPV) is an infectious disease that seriously harms the waterfowl breeding industry. The VP16 protein of α herpesvirus can bind to specific cis-acting elements upstream of the promoter of the immediate-early (IE, α) gene to promote the transcription of the IE gene, so it is also called the trans-inducer of IE gene (α-TIF). However, no studies on DPV α-TIF have been reported. This study investigated the DPV pUL48, a homolog of HSV-1 VP16, transcriptional activation region, target sequence, and viral protein affecting its transcriptional activation using a dual-luciferase reporter gene detection system, and pUL48 was identified as the α-TIF of DPV. (1) The regulation of pUL48 on DPV different gene promoters showed that pUL48 could activate all the promoters of IE genes (ICP4, ICP22, and ICP27) but not the promoters of early and late genes. (2) The activity of pUL48 to ICP4 and ICP22 promoters with different upstream lengths showed that pUL48 activated ICP4 and ICP22 promoters by acting on TAATGA (T) TAT element upstream of ICP4 promoter and TAATTATAT element upstream of ICP22 promoter, respectively. (3) Transcriptional activation of IE gene by truncated proteins of different lengths at the N-terminal of pUL48 was detected. The results showed that the transcriptional activation domain of pUL48 was amino acids 1-60 at the N-terminal, and amino acids 1-20 was its core region. In addition, it was found that pUL14, pUL46, and pUL47 significantly promoted the transcriptional activation of pUL48. The effects of loss of pUL47 and its nuclear localization signal on the nuclear entry and transcriptional activation function of pUL48 were further examined. The results showed that pUL47 could promote the nuclear entry of pUL48 through its nuclear localization signal at positions 40-50 and 768-777 amino acids, thus, enhancing the transcriptional activation function of pUL48 and synergistic promotion of viral gene transcription.

Keywords: duck plague virus; immediate early genes; pUL48; transcriptional activation domain; transcriptional activation function.