Translational Control of Eukaryotic
Gene Expression

Lp, Singh; Ar, Aroor; Aj, Wahba

doi:10.1159/000474972

Cited by 3 publications

(1 citation statement)

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“…The activity of mammalian eIF2B is subject to allosteric regulation by a variety of activators in itro (e.g. polyamines, NADH, NADPH [10][11][12] or inhibitors oNAD To learn more about the structure, function and regulation of mammalian eIF2B, we have isolated cDNA species for its subunits. The present report focuses on the α, β and δ subunits.…”

Section: Introductionmentioning

confidence: 99%

eIF2B, the guanine nucleotide-exchange factor for eukaryotic initiation factor 2. Sequence conservation between the α, β and δ subunits of eIF2B from mammals and yeast

Price

Mellor

Craddock

et al. 1996

Biochemical Journal

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The guanine nucleotide-exchange factor eIF2B mediates the exchange of GDP bound to translation initiation factor eIF2 for GTP. This exchange process is a key regulatory step for the control of translation initiation in eukaryotic organisms. To improve our understanding of the structure, function and regulation of eIF2B, we have obtained and sequenced cDNA species encoding all of its five subunits. Here we report the sequences of eIF2B beta and delta from rat. This paper focuses on sequence similarities between the alpha, beta and delta subunits of mammalian eIF2B. Earlier work showed that the amino acid sequences of the corresponding subunits of eIF2B in the yeast Saccharomyces cerevisiae (GCN3, GCD7 and GCD2) exhibit considerable similarity. We demonstrate that this is also true for the mammalian subunits. Moreover, alignment of the eIF2B alpha, beta and delta sequences from mammals and yeast, along with the sequence of the putative eIF2B alpha subunit from Caenorhabditis elegans and eIF2B delta from Schizosaccharomyces pombe shows that a large number of residues are identical or conserved between the C-terminal regions of all these sequences. This strong sequence conservation points to the likely functional importance of these residues. The implications of this are discussed in the light of results concerning the functions of the subunits of eIF2B in yeast and mammals. Our results also indicate that the large apparent differences in mobility on SDS/PAGE between eIF2B beta and delta subunits from rat and rabbit are not due to differences in their lengths but reflect differences in amino acid composition. We have also examined the relative expression of mRNA species encoding the alpha, beta, delta and epsilon subunits of eIF2B in a range of rat tissues by Northern blot analysis. As might be expected for mRNA species encoding subunits of a heterotrimeric protein, the ratios of expression levels of these subunits to one another did not vary between the different rat tissues examined (with the possible exception of liver). This represents the first analysis of the levels of expression of mRNA species encoding the different subunits of eIF2B.

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Section: Introductionmentioning

confidence: 99%

eIF2B, the guanine nucleotide-exchange factor for eukaryotic initiation factor 2. Sequence conservation between the α, β and δ subunits of eIF2B from mammals and yeast

Price

Mellor

Craddock

et al. 1996

Biochemical Journal

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The Effects of Pyrroloquinoline Quinone on Heme-Regulated eIF-2α Kinase and eIF-2B Activities in Eukaryotic Protein Synthesis

Konakanchi

Chen

Gallop

et al. 1997

Blood Cells, Molecules, and Diseases

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Traumatically Induced Axotomy Adjacent to the Soma Does Not Result in Acute Neuronal Death

Singleton¹,

et al. 2002

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Traumatic axonal injury (TAI), a consequence of traumatic brain injury (TBI), results from progressive pathologic processes initiated at the time of injury. Studies attempting to characterize the pathology associated with TAI have not succeeded in following damaged and/or disconnected axonal segments back to their individual neuronal somata to determine their fate. To address this issue, 71 adult male Sprague Dawley rats were subjected to moderate central fluid percussion injury and killed between 30 min and 7 d after injury. Antibodies to the C terminus of ␤-amyloid precursor protein (APP) identified TAI in continuity with individual neuronal somata in the mediodorsal neocortex, the hilus of the dentate gyrus, and the dorsolateral thalamus. These somata were followed with immunocytochemical markers of neuronal injury targeting phosphorylated 200 kDa neurofilaments (RMO-24), altered protein translation (phosphorylated eukaryotic translation initiation factor 2␣), and cell death [terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)], with parallel electron microscopic (EM) assessment. Despite the finding of TAI within 20-50 m of the soma, no evidence of cell death, long associated with proximal axotomy, was seen via TUNEL or routine light microscopy/electron microscopy. Rather, there was rapid onset (Ͻ6 hr after injury) subcellular change associated with impaired protein synthesis identified by EM, immunocytochemical, and Western blot analyses. When followed 7 d after injury, these abnormalities did not reveal dramatic progression. Rather, some somata showed evidence of potential reorganization and repair. This study demonstrates a novel somatic response to TAI in the perisomatic domain and also provides insight into the multifaceted pathology associated with TBI.

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Translational Control of Eukaryotic Gene Expression

Cited by 3 publications

References 0 publications

eIF2B, the guanine nucleotide-exchange factor for eukaryotic initiation factor 2. Sequence conservation between the α, β and δ subunits of eIF2B from mammals and yeast

eIF2B, the guanine nucleotide-exchange factor for eukaryotic initiation factor 2. Sequence conservation between the α, β and δ subunits of eIF2B from mammals and yeast

The Effects of Pyrroloquinoline Quinone on Heme-Regulated eIF-2α Kinase and eIF-2B Activities in Eukaryotic Protein Synthesis

Traumatically Induced Axotomy Adjacent to the Soma Does Not Result in Acute Neuronal Death

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