G0/G1 host cell cycle checkpoint dysregulation by virus

Host cell cycle is a highly regulated process during which chromosomes duplicated and cell division occurs. Resting cells that are not dividing are in a phase called G0. During division, the cell undergoes 4 distinct stages termed G1, S, G2, and M (mitosis). These periods of activity are separated by regulatory checkpoints at major transition phases. These checkpoints include G0/G1 which regulates the entry of a quiescent cell back into the cycle, G1/S, and G2/M.

Some viruses have evolved strategies to induce cell cycle entry in resting cells by promoting the G0/G1 checkpoint transition. For example, myxomavirus M-T5 mediates cell cycle progression beyond the G0/G1 checkpoint, with increased phosphorylation, ubiquitination and degradation of the cyclin-dependent kinase inhibitor p27/KIP1. HTLV-1 Tax induces also a cell cycle progression from G0/G1 phase.

Other viruses benefit from stopping host cells in G0/G1 checkpoint. For example SARS protein 3a inhibits Rb phosphorylation and blocks cell cycle progression at the G0/G1 phase. Epstein-Barr virus BZLF1 (Zta) mediates a G0/G1 growth arrest correlated with a p21 induction. Murine coronavirus p28 expression results in an accumulation of hypophosphorylated Rb and cyclin-dependent kinase (Cdk) inhibitor p21.

Matching UniProtKB/Swiss-Prot entries

27 entries grouped by protein (browse by keywords)

All proteins are shown (view only 24 complete proteome entries)

3 entries

Trans-activator protein BZLF1 (EB1) (Zebra)

Select_allDeselect_all
BZLF1_EBVA8
Epstein-Barr virus (strain AG876) (HHV-4) (Human herpesvirus 4) reference strain
BZLF1_EBVB9
Epstein-Barr virus (strain B95-8) (HHV-4) (Human herpesvirus 4) reference strain
BZLF1_EBVG
Epstein-Barr virus (strain GD1) (HHV-4) (Human herpesvirus 4) reference strain

1 entry

45 kDa immediate-early protein 2 (IE2)

IE247_HCMVT
Human cytomegalovirus (strain Towne) (HHV-5) (Human herpesvirus 5)

1 entry

Ankyrin repeat domain-containing protein M-T5 (M-T5 protein) (M5)

MT5_MYXVL
Myxoma virus (strain Lausanne) (MYXV) reference strain

4 entries

Non-structural protein 3b (ns3b) (Accessory protein 3b)

Select_allDeselect_all
NS3B_BCHK4
Bat coronavirus HKU4 (BtCoV) (BtCoV/HKU4/2004) reference strain
NS3B_BCHK5
Bat coronavirus HKU5 (BtCoV) (BtCoV/HKU5/2004) reference strain
NS3B_CVHSA
Human SARS coronavirus (SARS-CoV) (Severe acute respiratory syndrome coronavirus) reference strain

Non-structural protein 3b (ns3b) (Accessory protein 3b) (Protein X2)

NS3B_BC133
Bat coronavirus 133/2005 (BtCoV) (BtCoV/133/2005)

5 entries

Protein 7a (Accessory protein 7a)

Select_allDeselect_all
NS7A_BCHK9
Bat coronavirus HKU9 (BtCoV) (BtCoV/HKU9) reference strain

Non-structural protein 7a (ns7a) (Accessory protein 7a)

NS7A_CVHSA
Human SARS coronavirus (SARS-CoV) (Severe acute respiratory syndrome coronavirus) reference strain

Protein 7a (Accessory protein 7a) (Protein U122) (Protein X4)

NS7A_BC279
Bat coronavirus 279/2005 (BtCoV) (BtCoV/279/2005)
NS7A_BCHK3
Bat coronavirus HKU3 (BtCoV) (SARS-like coronavirus HKU3)
NS7A_BCRP3
Bat coronavirus Rp3/2004 (BtCoV/Rp3/2004) (SARS-like coronavirus Rp3)

1 entry

Non-structural protein ORF4a (ORF4a)

ORF4A_CVEMC
Human coronavirus EMC (isolate United Kingdom/H123990006/2012) (HCoV-EMC) reference strain

7 entries

Protein Tax-1 (Protein X-LOR) (Protein PX) (Trans-activating transcriptional regulatory protein of HTLV-1)

Select_allDeselect_all
TAX_HTL1C
Human T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain
TAX_HTL32
Human T-cell leukemia virus 3 (strain 2026ND) (HTLV-3) reference strain

Protein Tax-3 (Trans-activating transcriptional regulatory protein of HTLV-3)

TAX_HTLV2
Human T-cell leukemia virus 2 (HTLV-2) reference strain

Protein Tax-2 (Trans-activating transcriptional regulatory protein of HTLV-2)

TAX_HTL1A
Human T-cell leukemia virus 1 (strain Japan ATK-1 subtype A) (HTLV-1)
TAX_HTL1F
Human T-cell leukemia virus 1 (isolate Zaire EL subtype B) (HTLV-1)

Protein Tax-1 (Protein X-LOR) (Trans-activating transcriptional regulatory protein of HTLV-1)

TAX_HTL1L
Human T-cell leukemia virus 1 (isolate Melanesia mel5 subtype C) (HTLV-1)

Protein Tax-1 (Protein X-LOR) (Trans-activating transcriptional regulatory protein of HTLV-1)

TAX_HTL3P
Human T-cell leukemia virus 3 (strain Pyl43) (HTLV-3)

Protein Tax-3 (Trans-activating transcriptional regulatory protein of HTLV-3)

1 entry

Protein UL27

UL27_HCMVM
Human cytomegalovirus (strain Merlin) (HHV-5) (Human herpesvirus 5) reference strain

4 entries

Viral transcription factor IE2 (IE2) (Protein UL122)

Select_allDeselect_all
VIE2_HCMVA
Human cytomegalovirus (strain AD169) (HHV-5) (Human herpesvirus 5) reference strain
VIE2_HCMVM
Human cytomegalovirus (strain Merlin) (HHV-5) (Human herpesvirus 5) reference strain
VIE2_MUHVS
Murid herpesvirus 1 (strain Smith) (MuHV-1) (Mouse cytomegalovirus) reference strain

Immediate-early protein 2 (IE2)

VIE2_HCMVT
Human cytomegalovirus (strain Towne) (HHV-5) (Human herpesvirus 5)