Page 333 - Avian Virology: Current Research and Future Trends

324 | Coppo et al.

Table 11.1 Continued
Open Predicted Apparent
reading Predicted molecular molecular
frame amino acid mass mass
(ORF) Protein length a (kDa) b (kDa) Putative function Transcribed References
UL[–1] c Protein LORF2 (spliced) d 501 57.6 73 Unknown. Nuclear γ Ziemann et al. (1998b);
(47 + 454) localization L II Mahmoudian et al. (2012);
Nadimpalli et al. (2017)
ICP4 Transcriptional regulator 1491 161.8 200 Gene regulation IE Johnson et al. (1995b);
Infected cell protein 4 Mahmoudian et al. (2012)
(ICP4)
US10 Virion protein US10 279 30.8 ND Unknown E I Wild et al. (1996)
sORF 4/3 Protein SORF3 295 32.1 ND Unknown L II Wild et al. (1996);
Mahmoudian et al. (2012)
US2 Virion protein US2 230 22.3 ND Unknown – possibly L I Mahmoudian et al. (2012)
envelope associated
US3 Serine/threonine protein 477 53.8 ND Protein phosphorylation γ1 Kongsuwan et al. (1995);
kinase US3 – apoptosis – nuclear E II Mahmoudian et al. (2012)
egress
UL47 c Tegument protein 625 67 67.5 Possibly gene regulation γ2 Kongsuwan et al. (1995);
VP13/14 d E II Helferich et al. (2007a,b);
Mahmoudian et al. (2012)
US4 c Glycoprotein G d 293 32 52 Immune-modulation γ (α, β) Kongsuwan et al. (1993a);
L III Sun and Zhang (2005);
Devlin et al. (2006b,
2010); Helferich et al.
(2007a); Mahmoudian et
al. (2012)
US5 c Glycoprotein J d,e 996, 611 107, 67 85, 115, Virulence. Cell egress L III Veits et al. (2003a); Fuchs
160, 200 γ2 et al. (2005); Mahmoudian
et al. (2012)
US6 c Glycoprotein D d 435 38.7 65, 70 Cell attachment – binds E/L II Mahmoudian et al. (2012);
to cell surface receptors Pavlova et al. (2013)
US7 c Glycoprotein I d 363 38.2 62 Cell-to-cell spread – E/L II Devlin et al. (2006a);
complexed with gE to Mahmoudian et al. (2012);
form Fc-receptor Pavlova et al. (2013)
US8 c Glycoprotein E d 500 55.4 75 Cell-to-cell spread – E/L I Devlin et al. (2006a);
complexed with gI to Mahmoudian et al. (2012);
form Fc-receptor Pavlova et al. (2013)
US9 c Membrane protein US8A d 261 27.9 37, 25 L III Mahmoudian et al. (2012);
Pavlova et al. (2013)

a Based on the sequence of ILTV strain CSW1 (JX646899.1).
b Where predicted molecular masses have not been published these were estimated using predicted amino acid sequences of the ILTV strain
CSW1 and a Protein Molecular Weight Calculator tool (http://www.sciencegateway.org/tools/index.html).
c A gene-specific deletion mutant has been generated for this ORF.
d Polyclonal antibody has been raised against this protein.
e Monoclonal antibody has been raised against this protein.
E, early; E/L, early/late; IE, immediate early; L, late; ND, not determined; P, precursor.

exhibited an attenuated phenotype, causing less severe clinical to be undertaken. Also, ultrastructural studies to investigate varia-
signs than the parent strain and only minor microscopic lesions tions in viral assembly, maturation and egress associated with the
in the trachea, despite viral titres in tracheal swabs that were expression (or lack thereof) of these ILTV unique peptides would
not significantly different at 6 days after infection (García et al., be useful to further characterize their role in these processes.
2016). Although inconclusive, the data gathered so far indicates The two other ILTV-specific ORFS, UL0 and UL[–1], located
that ORFs A–E have important and possibly redundant roles in upstream to the UL1 ORF, are translated from spliced mRNA
viral replication and viral egress, and at least for ORF C, its role in species (Ziemann et al., 1998b). Both pUL0 and pUL[–1] locate
cell-to-cell spread but not in viral replication per se appears to be to the nucleus of infected cells (Ziemann et al., 1998b) and are
associated with the capacity of the virus to cause tissue disruption categorized as late (γ) transcription genes (Ziemann et al., 1998b;
and pathology in vivo. Future work to determine whether these Mahmoudian et al., 2012). Isolation of a deletion mutant lacking
proteins are only expressed during infection or are a structural UL0 demonstrated the dispensable nature of this gene, where
part of the virion (tegument- or membrane-associated) remains the lack of UL0 resulted in a moderate delay in viral replication