Dissection of functional domains in the adenovirus 2 early 1b 55k polypeptide by suppressor-linker insertional mutagenesis

Yew, P.Renee; Kao, C. Y.; Berk, Arnold

doi:10.1016/0042-6822(90)90147-j

Cited by 77 publications

(96 citation statements)

References 46 publications

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“…Thus, the same mutations that abolish formation of a single cytoplasmic inclusion body and cytoplasmic sequestration of Mre11 also eliminate the interaction with the MRN subunit. These results are surprising in light of previous reports, that a fourresidue insertion at amino-acid position 354, situated within the putative zinc finger of the Ad2 E1B protein (E1B-H354) (Yew et al, 1990), eliminates the interaction of the Ad2 protein with and cytoplasmic sequestration of Mre11 (Carson et al, 2003;Liu et al, 2005).…”

Section: Resultscontrasting

confidence: 82%

“…Finally, we suggest that the loss of binding to Mre11 interferes with the inhibition of MRN function and thus may be detrimental to Ad5 E1B-55K transforming function (discussed below). It should be noted, however, that the Mre11 binding-deficient mutant Ad2 E1B-H354 (Yew et al, 1990;Carson et al, 2003) is not defective for transformation of primary BRK cells (Yew and Berk, 1992). This difference in transforming activity of the E1B-55K mutant is unclear.…”

Section: Discussionmentioning

confidence: 98%

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Adenovirus type 5 early region 1B 55-kDa oncoprotein can promote cell transformation by a mechanism independent from blocking p53-activated transcription

Härtl

Zeller²,

Blanchette

et al. 2008

Oncogene

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Inhibition of p53-activated transcription is an integral part of the mechanism by which early region 1B 55K oncoprotein (E1B-55K) from adenovirus type 5 (Ad5) contributes to complete cell transformation in combination with Ad E1A. In addition, more recent data suggest that the mode of action of the Ad protein during transformation may involve additional functions and other protein interactions. In the present study, we performed a comprehensive mutational analysis to assign further transforming functions of Ad5 E1B-55K to distinct domains within the viral polypeptide. Results from these studies show that the functions required for transformation are encoded within several patches of the 55K primary sequence, including several clustered cysteine and histidine residues, some of which match the consensus for zinc fingers. In addition, two amino-acid substitutions (C454S/C456S) created a 55K mutant protein, which had substantially reduced transforming activity. Interestingly, the same mutations neither affected binding to p53 nor inhibition of p53-mediated transactivation. Therefore, an activity necessary for efficient transformation of primary rat cells can be separated from functions required for inhibition of p53-stimulated transcription. Our data indicate that this activity is linked to the ability of the Ad5 protein to bind to components of the Mre11/Rad50/NBS1 DNA doublestrand break repair complex, and/or its ability to assemble multiprotein aggregates in the cytoplasm and nucleus of transformed rat cells. These results introduce a new function for Ad5 E1B-55K and suggest that the viral protein contributes to cell transformation through p53 transcription-dependent and -independent pathways.

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Section: Resultscontrasting

confidence: 82%

Section: Discussionmentioning

confidence: 98%

Adenovirus type 5 early region 1B 55-kDa oncoprotein can promote cell transformation by a mechanism independent from blocking p53-activated transcription

Härtl

Zeller²,

Blanchette

et al. 2008

Oncogene

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“…Several of these products have been found to be produced in normal lytic infection only at later times. 496R appears to derive transforming activity through interactions with the cellular turnout suppressor p53 (Sarnow et al, 1982b;Kao et aL, 1990;Yew & Berk, 1992). It is possible that 156R, 84R or 93R could function in transformation or replication by interfering with or enhancing this interaction or some other function of 496R.…”

Section: Discussionmentioning

confidence: 99%

“…However, generation of stable transformants of primary rodent cells requires E1B proteins. The 19K and 55K E1B proteins can function independently, but transforming efficiency is increased when both are expressed (Bernards et al, 1986;Barker & Berk, 1987;White & Cipriani, 1990;Yew et al, 1990;McLorie et al, 1991;Zhang et al, 1992). The 19K protein appears to protect against programmed cell death induced as a consequence of disruption of growth control pathways by E1A (White et al, 1992;Rao et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

“…The 19K protein appears to protect against programmed cell death induced as a consequence of disruption of growth control pathways by E1A (White et al, 1992;Rao et al, 1992). The 55K protein may derive some or all of its transforming activity from interactions with and inactivation of the cellular p53 tumour suppressor (Sarnow et al, 1982b;Kao et at., 1990;Yew & Berk, 1992 cell metabolism (Babiss & Ginsberg, 1984;Logan et al, 1984;Babiss et al, 1985;Halbert et at., 1985;Pilder et al, 1986: Bernards et al, 1986Barker & Berk, 1987;Sandler & Ketner, 1989;Bridge & Ketner, 1990, Leppard & Shenk, 1989, Yew et al, 1990McLorie et al, 1991). With serotype 12 (Adl2), the corresponding 54K protein is required for viral DNA replication (Shiroki et al, 1986;Breiding et al, 1988;Mak & Mak, 1990;Zhang et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

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Characterization of the 55K adenovirus type 5 E1B product and related proteins

Takayesu

Teodoro

Whalen

et al. 1994

Journal of General Virology

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In addition to major proteins of 19K and 55K (176 and 496 residues, 176R and 496R, respectively), early region 1B (E1B) of human adenovirus type 5 (Ad5) is predicted to encode at least three other polypeptides of 156R, 93R and 84R that share 79 amino-terminal residues with 496R. We have used a series of specific antipeptide sera to identify and partially characterize these proteins. 84R was produced in large amounts, 156R somewhat less, and 93R at very low levels. Synthesis of 176R, 496R, as well as the E2A 72K DNA-binding protein commenced shortly after that of E1A proteins in Ad5-infected KB cells. Production of 156R, 93R and 84R began somewhat later, but prior to the synthesis of the late structural protein IX and hexon. 156R, which is composed of the 79 amino-terminal and 77 carboxy-terminal amino acids of 496R, migrated on SDS-PAGE as two species which appeared to differ by their degree of phosphorylation. 156R and 496R yielded identical tryptic phosphopeptides that contained both phosphoserine and phosphothreonine, and one of these was immunoprecipitated by a serum specific for the carboxy terminus. These results suggested that Ser-490 and/or Ser-491 as well as Thr-495 are major sites of phosphorylation in these proteins.

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The biology of the adenovirus E1B 55K protein

Hidalgo

Dobner

et al. 2019

FEBS Letters

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The adenovirus E1B 55K (E1B) protein plays major roles in productive adenoviral infection and cellular transformation. Interest in E1B increased because of the potential of adenoviruses as therapeutic vectors, and the E1B gene is commonly deleted from adenovirus vectors for anticancer therapy. E1B activities are spatiotemporally regulated through SUMOylation and phosphorylation, and through interactions with multiple partners that occur presumably at different intracellular sites and times postinfection. E1B is implicated in the formation of viral replication compartments and regulates viral genome replication and transcription, transcriptional repression, degradation of cellular proteins, and several intranuclear steps of viral late mRNA biogenesis. Here, we review advances in our understanding of E1B during productive adenovirus replication and discuss fundamental aspects that remain unresolved.The adenovirus E1B 55K protein (called E1B throughout this review) plays key roles during productive viral replication and contributes to oncogenic transformation. The E1B gene is usually deleted or modified in oncolytic adenoviruses because such viruses preferentially replicate in and kill cancer cells (reviewed in [1,2]). Although structural data for the 496 amino acid (aa) polypeptide are scarce, some structural or functional motifs are known or have been proposed, and the E1B protein may contain intrinsically disordered regions (IDR). E1B activities are regulated by posttranslational modifications (PTMs) that impact on both intracellular localization and the interactions that E1B establishes with viral and cellular proteins. E1B acts as a small ubiquitin-like modifier (SUMO)-1 ligase for p53 and participates in the polyubiquitylation-induced degradation of cellular targets that would otherwise interfere with viral replication. E1B also promotes viral replication through repression of interferon (IFN)-stimulated genes (ISG) and p53 regulation. Of note, efficient viral DNA replication depends on the formation of adenoviral replication compartments (RCs), another process in which E1B is involved. Furthermore, E1B interacts with viral RNA and this interaction optimizes production and splicing of viral late mRNAs. Yet, many aspects of the biology of E1B remain to be elucidated, including the protein's threedimensional structure and the molecular mechanisms whereby E1B regulates viral genome replication and gene expression. Most of the knowledge of E1B comes from the study of the human serotypes 2 and 5 from species C; however, sequences and functional features from other adenovirus species have also been described. A very complete review of the E1B protein Abbreviations CRM1, chromosome region maintenance 1 protein homolog; CDK, cyclin-dependent kinase; E1B-AP5, E1B-associated protein 5; eIF4E, eukaryotic translation initiation factor 4E; hnRNP, heteronuclear ribonucleoprotein; LH3, hexon-interlacing protein LH3; I-TASSER, iterative threading ASSEmbly refinement; Mre11, meiotic recombination 11; Nxf1/Tap, nuclear RNA expo...

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Dissection of functional domains in the adenovirus 2 early 1b 55k polypeptide by suppressor-linker insertional mutagenesis

Cited by 77 publications

References 46 publications

Adenovirus type 5 early region 1B 55-kDa oncoprotein can promote cell transformation by a mechanism independent from blocking p53-activated transcription

Adenovirus type 5 early region 1B 55-kDa oncoprotein can promote cell transformation by a mechanism independent from blocking p53-activated transcription

Characterization of the 55K adenovirus type 5 E1B product and related proteins

The biology of the adenovirus E1B 55K protein

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