Rapid turnover of adenovirus E1A is determined through a co-translational mechanism that requires an aminoterminal domain.

Slavicek, James M.; Jones, Nicholas; Richter, Joel D.

doi:10.1002/j.1460-2075.1988.tb03184.x

Cited by 24 publications

(29 citation statements)

References 39 publications

(36 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The ubiquitin system may recognize abnormal/truncated/misfolded proteins, but not their normal counterparts. For example, a truncated form of E1A adenovirus protein (amino acid residues 1-85) is much more sensitive to degradation then the wild type (1-289) protein (29,43). The case of p53 is even more illustrative, although the direction appears to be "opposite."…”

Section: Resultsmentioning

confidence: 99%

Ubiquitin-mediated Processing of NF-κB Transcriptional Activator Precursor p105

Orian

Whiteside

Israël

et al. 1995

Journal of Biological Chemistry

143

View full text Add to dashboard Cite

In most cases, the transcriptional factor NF-B is a heterodimer consisting of two subunits, p50 and p65, which are encoded by two distinct genes of the Rel family. p50 is translated as a precursor of 105 kDa. The C-terminal domain of the precursor is rapidly degraded, forming the mature p50 subunit consisted of the N-terminal region of the molecule. The mechanism of generation of p50 is not known. It has been suggested that the ubiquitin-proteasome system is involved in the process; however, the specific enzymes involved and the mechanism of limited proteolysis, in which half of the molecule is spared, have been obscure. Palombella and colleagues (Palombella, V. J., Rando, O. J., Goldberg, A. L., and Maniatis, T. (1994) Cell 78, 773-785) have shown that ubiquitin is required for the processing in a cell-free system of a truncated, artificially constructed, 60-kDa precursor. They have also shown that proteasome inhibitors block the processing both in vitro and in vivo. In this study, we demonstrate reconstitution of a cell-free processing system and demonstrate directly that: (a) the ubiquitin-proteasome system is involved in processing of the intact p105 precursor, (b) conjugation of ubiquitin to the precursor is an essential intermediate step in the processing, (c) the recently discovered novel species of the ubiquitin-carrier protein, E2-F1, that is involved in the conjugation and degradation of p53, is also required for the limited processing of the p105 precursor, and (d) a novel, ϳ320-kDa species of ubiquitin-protein ligase, is involved in the process. This novel enzyme is distinct from E6-AP, the p53-conjugating ligase, and from E3␣, the "N-end rule" ligase.NF-B and other members of the Rel family of transcriptional activators have recently gained considerable attention because of their unique mechanism of activation, and their active role in cytoplasmic-nuclear signaling in response to a variety of extracellular stimuli. In most cases, NF-B is a heterodimeric complex composed of p50 and p65 subunits. p50 is initially synthesized as an inactive 105-kDa precursor that is processed to the mature protein following removal of the Cterminal domain of the molecule. A second precursor molecule, p100, gives rise to the p52 DNA-binding subunit of NF-B, probably via a similar mechanism. The heterodimeric complex was originally identified as an inducible B cell-specific transcription factor able to bind the light chain enhancer (1). NF-B is now recognized to be a ubiquitously expressed factor that is present as an inactive ternary complex in the cytosol of most cells. In this ternary complex, a third inhibitory protein belonging to the IB family is associated with the heterodimer (for recent reviews, see Refs. 2-4). A wide range of stimuli such as bacterial products, parasites, viruses and viral products, inflammatory cytokines, T cells, B cells, fibroblast mitogens, protein synthesis inhibitors, physical and oxidative stresses, and drugs lead to accelerated processing of the precursor, degradation of the inhibitor, ...

show abstract

Section: Resultsmentioning

confidence: 99%

Ubiquitin-mediated Processing of NF-κB Transcriptional Activator Precursor p105

Orian

Whiteside

Israël

et al. 1995

Journal of Biological Chemistry

143

View full text Add to dashboard Cite

show abstract

“…The GAL4 fusion proteins are all expressed at equivalent levels (within two-to threefold) in CHO cells (data not shown). 1 amino-terminal sequence, an important determinant of protein stability (Bachmair et al 1986;Slavicek et al 1988); and (2) facilitate specific control experiments. Deletion of the first 19 or 76 amino acids of IE protem results in GAL4-IE derivatives, GAL4-IE (30-1460) and GAL4-IE (77-1460), Mrhich fail to activate E4 transcription.…”

Section: Ie Protein Amino Acids 1-34 Are Critical For Activation Of Pmentioning

confidence: 99%

Transcriptional activation by the pseudorabies virus immediate early protein.

Martin

Lillie²,

Green³

1990

Genes & Development

View full text Add to dashboard Cite

The pseudorabies virus immediate early (IE] protein is a potent, promiscuous activator of viral and cellular gene transcription. The promiscuous action of IE protein has led to the suggestion that it functions by an unusual mechanism. Here, we show that IE protein has the two essential features of a typical cellular activator: (1) a transcriptional activation region, and (2) a separable region that directs IE protein, or an unrelated activation region, to the vicinity of the promoter. We map the IE protein activation region to 34 amino acids, demonstrate that it is comparable in strength to the strongest known activation region, and show that it is required for the transcriptional activity of the intact IE protein. The 34-amino-acid IE protein activation region is highly acidic. We provide evidence that it uses the same cellular target as an unrelated acidic activator and a different target from that of a nonacidic activator. Our results provide insight into the function of promiscuous eukaryotic transcriptional activators.

show abstract

“…We subsequently showed that the stability of this protein was not merely a function of bacterial expression, since ElA synthesized in a rabbit reticulocyte lysate from an SP6-derived mRNA was also stable in injected oocytes. When ElA was synthesized in oocytes from injected mRNA, however, it exhibited its characteristic short half-life (44). Thus, the half-life of ElA appeared to be related to the translation of its message.…”

mentioning

confidence: 99%

“…amino-terminal region of ElA protein that included the penultimate residue, an arginine, was important for its degradation in mRNA-injected oocytes (44).…”

mentioning

confidence: 99%

The degradation sequence of adenovirus E1A consists of the amino-terminal tetrapeptide Met-Arg-His-Ile.

Simon¹,

Richter²

1990

Mol. Cell. Biol.

View full text Add to dashboard Cite

The adenovirus E1A gene product is a potent transcriptional activator and nuclear oncoprotein. Like other regulatory proteins, E1A has a short half-life, in the range of 30 to 120 min. This short half-life, which was measured in cells synthesizing E1A, is not observed in cells injected with E1A protein made in bacteria or in vitro. In these cases, E1A is essentially refractory to degradation. In an attempt to reconcile this apparent paradox, we suggested that E1A was marked for degradation during its synthesis. Furthermore, we showed that a domain in the amino terminus of E1A was required for rapid degradation in cells translating E1A mRNA (J. M. Slavicek, N. C. Jones, and J. D. Richter, EMBO J. 7:3171-3180, 1988). In this study, we have used Xenopus laevis oocytes injected with mRNAs encoding altered E1A proteins to show that the amino-terminal tetrapeptide Met-Arg-His-Ile is required for E1A degradation. Even conservative amino acid substitutions in this degradation sequence render it nonfunctional. This degradation sequence can function as a transferable signal, since it induces instability when fused to another normally stable protein. Furthermore, the degradation sequence requires a proximity of no more than six residues from the amino terminus for activity. These data suggest that a trans-acting factor recognizes the amino terminus of E1A during the translation of its message to mark the protein for subsequent destruction.

show abstract

Rapid turnover of adenovirus E1A is determined through a co-translational mechanism that requires an aminoterminal domain.

Cited by 24 publications

References 39 publications

Ubiquitin-mediated Processing of NF-κB Transcriptional Activator Precursor p105

Ubiquitin-mediated Processing of NF-κB Transcriptional Activator Precursor p105

Transcriptional activation by the pseudorabies virus immediate early protein.

The degradation sequence of adenovirus E1A consists of the amino-terminal tetrapeptide Met-Arg-His-Ile.

Contact Info

Product

Resources

About