Iltovirus (taxid:180255)



Enveloped, spherical to pleomorphic, 120-200 nm in diameter, T=16 icosahedral symmetry. Capsid consists of 162 capsomers and is surrounded by an amorphous tegument. Glycoproteins complexes are embeded in the lipid envelope.


Monopartite, linear, dsDNA genome of about 150 kb. The genome contains terminal and internal reiterated sequences. The genome sequence is repeated at one end. Each virion contains multiple isomeric forms of the genome


Each viral transcript usually encodes a single protein and has a promoter/regulatory sequence, a TATA box, a transcription initiation site, a 5' leader sequence of 30-300 bp (not translated), a 3' nontranslated sequence of 10-30 bp, and a poly A signal. There are many gene overlaps. There are only few spliced genes. Some of the expressed ORFs are antisense to each other. Some ORFs can be accessed from more than one promoter. There are some non-coding genes.

There are three types of genes: immediate-early, early and late. The immediate-early genes are transcribed immediately after infection and ensure the transcription of early genes, which encode the proteins necessary for the viral replication. The late genes mostly encode structural proteins. Standing apart are genes expressed during latency.

The viral proteins VHS and ICP27 are involved in shut-off of host protein translation in order to ensure the selective expression of viral proteins versus cellular proteins.




Lytic replication:

  1. Attachment of the viral gB, gC, gD and gH proteins to host receptors mediates endocytosis of the virus into the host cell.
  2. Fusion with the plasma membrane to release the core and the tegument proteins into the host cytoplasm.
  3. The capsid is transported to the nuclear pore where the viral DNA is released into the nucleus.
  4. Transcription of immediate early genes which promote transcription of early genes and protect the virus against innate host immunity.
  5. Transcription of early viral mRNA by host polymerase II, encoding proteins involved in replication of the viral DNA.
  6. A first round of circular genome amplification occurs by bidirectional replication
  7. Synthesis of linear concatemer copies of viral DNA by rolling circle.
  8. Transcription of late mRNAs by host polymerase II, encoding structural proteins.
  9. Assembly of the virus in nuclear viral factories and budding through the inner lamella of the nuclear membrane which has been modified by the insertion of herpes glycoproteins, throughout the Golgi and final release at the plasma membrane.

Latent replication : replication of circular viral episome in tandem with the host cell DNA using the host cell replication machinery.

Host-virus interaction

Cell-cycle modulation

The conserved UL24 family of human alpha, beta and gamma herpesviruses induces a cell cycle arrest at G2/M transition through inactivation of the host cyclinB/cdc2 complex. Iltoviruses encode an UL24 homolog that should fullfill this role.

Host splicing inhibition

PsHV-1 UL54 is an alternative splicing regulator of host mRNA.

Matching UniProtKB/Swiss-Prot entries

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78 entries grouped by strain

71 entries

Psittacid herpesvirus 1 (isolate Amazon parrot/-/97-0001/1997) (PsHV-1) (Pacheco's disease virus) reference strain

GE_PSHV1 Envelope glycoprotein E (gE)
LTP_PSHV1 Large tegument protein deneddylase (EC (EC 3.4.22.-)
SCAF_PSHV1 Capsid scaffolding protein (Capsid protein P40) (Protease precursor) (pPR) [Cleaved into: Assemblin ...
GI_PSHV1 Envelope glycoprotein I
GD_PSHV1 Envelope glycoprotein D (gD)
US03_PSHV1 Protein kinase US3 homolog (EC
GL_PSHV1 Envelope glycoprotein L (gL)
GM_PSHV1 Envelope glycoprotein M (gM)
TEG2_PSHV1 Tegument protein UL11
AN_PSHV1 Alkaline nuclease (EC 3.1.-.-)
UL13_PSHV1 Serine/threonine-protein kinase UL13 (EC
RIR2_PSHV1 Ribonucleoside-diphosphate reductase small subunit (EC (Ribonucleotide reductase small ...
RIR1_PSHV1 Ribonucleoside-diphosphate reductase large subunit (R1) (EC (Ribonucleotide reductase ...
DPOL_PSHV1 DNA polymerase catalytic subunit (EC (EC
TRM1_PSHV1 Tripartite terminase subunit 1
GB_PSHV1 Envelope glycoprotein B (gB)
KITH_PSHV1 Thymidine kinase (EC
GH_PSHV1 Envelope glycoprotein H (gH)
GN_PSHV1 Envelope glycoprotein N
GK_PSHV1 Envelope glycoprotein K (Syncytial protein)
ICP4_PSHV1 Major viral transcription factor ICP4 homolog
GG_PSHV1 Glycoprotein G
TEG5_PSHV1 Tegument protein UL47 homolog
US10_PSHV1 Virion protein US10 homolog
UL01_PSHV1 Uncharacterized protein UL-1
UNG_PSHV1 Uracil-DNA glycosylase (UDG) (EC (UNG)
HELI_PSHV1 DNA replication helicase (EC 3.6.4.-)
PORTL_PSHV1 Portal protein
CEP1_PSHV1 Cytoplasmic envelopment protein 1
HEPA_PSHV1 DNA helicase/primase complex-associated protein (HEPA) (Primase-associated factor)
OBP_PSHV1 Replication origin-binding protein (OBP) (OriBP)
TEG3_PSHV1 Tegument protein UL14
CEP2_PSHV1 Cytoplasmic envelopment protein 2
CVC1_PSHV1 Capsid vertex component 1
TRM3_PSHV1 Tripartite terminase subunit 3 (EC 3.1.-.-) (Terminase large subunit)
TRX2_PSHV1 Triplex capsid protein 2
MCP_PSHV1 Major capsid protein (MCP)
UL20_PSHV1 Protein UL20
TG21_PSHV1 Tegument protein UL21
GC_PSHV1 Envelope glycoprotein C
PAP_PSHV1 DNA polymerase processivity factor (DNA-binding protein UL42) (Polymerase accessory protein) (PAP)
SHUT_PSHV1 Virion host shutoff protein (Vhs) (EC 3.1.27.-)
TRX1_PSHV1 Triplex capsid protein 1
ITP_PSHV1 Inner tegument protein
SCP_PSHV1 Small capsomere-interacting protein
NEC2_PSHV1 Nuclear egress protein 2
TRM2_PSHV1 Tripartite terminase subunit 2
UL32_PSHV1 Packaging protein UL32
NEC1_PSHV1 Nuclear egress protein 1
DNBI_PSHV1 Major DNA-binding protein
CVC2_PSHV1 Capsid vertex component 2
UL24_PSHV1 Protein UL24
EV45_PSHV1 Envelope protein UL45
ATI2_PSHV1 Alpha trans-inducing factor (Tegument protein UL46) (Tegument protein VP11/12)
VP22_PSHV1 Tegument protein VP22
DUT_PSHV1 Deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase) (EC (dUTP pyrophosphatase)
TEG7_PSHV1 Tegument protein UL51
PRIM_PSHV1 DNA primase (EC 2.7.7.-)
ICP27_PSHV1 mRNA export factor (Immediate-early protein IE63) (Infected cell protein 27) (ICP27)
ORF3_PSHV1 Uncharacterized protein sORF3/4
ORF2_PSHV1 Uncharacterized protein sORF2
US02_PSHV1 Uncharacterized protein US2
UL03_PSHV1 Uncharacterized protein UL3
NP04_PSHV1 Nuclear protein UL4
UL15B_PSHV1 Large terminase protein homolog UL15b
UL43_PSHV1 Membrane protein UL43
ORFE_PSHV1 Uncharacterized protein ORFE
ORFD_PSHV1 Uncharacterized protein ORFD
ORFC_PSHV1 Uncharacterized protein ORFC
ORFB_PSHV1 Uncharacterized protein ORFB
ORFA_PSHV1 Uncharacterized protein ORFA

5 entries

Infectious laryngotracheitis virus (strain Thorne V882) (ILTV) (Gallid herpesvirus 1)

SCAF_ILTVT Capsid scaffolding protein (Capsid protein P40) (Protease precursor) (pPR) [Cleaved into: Assemblin ...
GB_ILTVT Envelope glycoprotein B (gB)
KITH_ILTVT Thymidine kinase (EC
UL24_ILTVT Protein UL24 homolog (ORF 3)
CVC2_ILTVT Capsid vertex component 2

1 entry

Infectious laryngotracheitis virus (strain 632) (ILTV) (Gallid herpesvirus 1)

GB_ILTV6 Envelope glycoprotein B (gB)

1 entry

Infectious laryngotracheitis virus (strain SA-2) (ILTV) (Gallid herpesvirus 1)

GB_ILTVS Envelope glycoprotein B (gB)