Degradation of a Novel DNA Damage Response Protein, Tankyrase 1 Binding Protein 1, following Adenovirus Infection

Abstract

Infection by most DNA viruses activates a cellular DNA damage response (DDR), which may be to the detriment or advantage of the virus. In the case of adenoviruses, they neutralize antiviral effects of DDR activation by targeting a number of proteins for rapid proteasome-mediated degradation. We have now identified a novel DDR protein, tankyrase 1 binding protein 1 (TNKS1BP1) (also known as Tab182), which is degraded during infection by adenovirus serotype 5 and adenovirus serotype 12. In both cases, degradation requires the action of the early region 1B55K (E1B55K) and early region 4 open reading frame 6 (E4orf6) viral proteins and is mediated through the proteasome by the action of cullin-based cellular E3 ligases. The degradation of Tab182 appears to be serotype specific, as the protein remains relatively stable following infection with adenovirus serotypes 4, 7, 9, and 11. We have gone on to confirm that Tab182 is an integral component of the CNOT complex, which has transcriptional regulatory, deadenylation, and E3 ligase activities. The levels of at least 2 other members of the complex (CNOT3 and CNOT7) are also reduced during adenovirus infection, whereas the levels of CNOT4 and CNOT1 remain stable. The depletion of Tab182 with small interfering RNA (siRNA) enhances the expression of early region 1A proteins (E1As) to a limited extent during adenovirus infection, but the depletion of CNOT1 is particularly advantageous to the virus and results in a marked increase in the expression of adenovirus early proteins. In addition, the depletion of Tab182 and CNOT1 results in a limited increase in the viral DNA level during infection. We conclude that the cellular CNOT complex is a previously unidentified major target for adenoviruses during infection.IMPORTANCE Adenoviruses target a number of cellular proteins involved in the DNA damage response for rapid degradation. We have now shown that Tab182, which we have confirmed to be an integral component of the mammalian CNOT complex, is degraded following infection by adenovirus serotypes 5 and 12. This requires the viral E1B55K and E4orf6 proteins and is mediated by cullin-based E3 ligases and the proteasome. In addition to Tab182, the levels of other CNOT proteins are also reduced during adenovirus infection. Thus, CNOT3 and CNOT7, for example, are degraded, whereas CNOT4 and CNOT1 are not. The siRNA-mediated depletion of components of the complex enhances the expression of adenovirus early proteins and increases the concentration of viral DNA produced during infection. This study highlights a novel protein complex, CNOT, which is targeted for adenovirus-mediated protein degradation. To our knowledge, this is the first time that the CNOT complex has been identified as an adenoviral target.

The biology of the adenovirus E1B 55K protein

“…E1B has been proposed to act as the substrate recognition component of this complex . The growing list of known targets includes components of the MRN complex, meiotic recombination 11 (Mre11) and Rad 50 , the Bloom helicase , DNA ligase IV , ATRX , p53 , Tat interactive protein‐60 (Tip60) , SPOC1 , Tab 182 , integrin α3 , and SWI/SNF Related, Matrix Associated, Actin Dependent Regulator Of Chromatin, Subfamily A Like 1 . E1B is also responsible for targeting Daxx for degradation, independent of E4Orf6 in HAdV5‐infected cells .…”

The human adenovirus type 5 E1B 55kDa protein interacts with RNA promoting timely DNA replication and viral late mRNA metabolism

“…A repression domain for interferon target genes has been mapped to the E1B 55K C-terminus [9], while its N-terminus can interact with the tumor supressor p53, tethering a repressor domain that inhibits p53-dependent transcription [10,11]. The interaction with the viral early E4 Orf6 protein and the cellular proteins Cullin 5, Elongins B and C, and Rbx1 is required for assembly of an E3 Ubiquitin ligase complex [12] that promotes polyubiquitylation and degradation of a growing number of cellular substrates that include components of the DNA Damage Response (DDR), such as Mre11, Rad 50 [13,14], the Bloom helicase [15] and DNA ligase IV [16,17], as well as, ATRX [18], p53 [12,19], Tip 60 [20], SPOC 1 [21], Tab182 [22], and α3 integrin [23]. Interestingly, E1B 55K is also responsible for degradation of the PML nuclear bodies component Daxx without the assembly of the E4 Orf6-dependent Cullin5 E3 Ubiquitin ligase complex [24].…”

Host Blood Gene Signatures Can Detect the Progression to Severe and Cerebral Malaria

“…Specifically, Chinn et al reported that SNPs in IDH1 were significantly associated with HIV infection, three of which were found in transcription factors binding sites (Chinn et al, 2010). Similarly, CNOT7 and ADAP2, both down-regulated in severe malaria, were previously reported to have a protective role during viral infections (Shu et al, 2015;Chalabi Hagkarim et al, 2018). Of the up-regulated genes in severe malaria, TRA2A was found to promote human influenza A virus replication by inhibiting the splicing of the NS segment of its mRNA (Zhu et al, 2020).…”