1
|
Cristiano L. The pseudogenes of eukaryotic translation elongation factors (EEFs): Role in cancer and other human diseases. Genes Dis 2022; 9:941-958. [PMID: 35685457 PMCID: PMC9170609 DOI: 10.1016/j.gendis.2021.03.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 03/29/2021] [Indexed: 02/06/2023] Open
Abstract
The eukaryotic translation elongation factors (EEFs), i.e. EEF1A1, EEF1A2, EEF1B2, EEF1D, EEF1G, EEF1E1 and EEF2, are coding-genes that play a central role in the elongation step of translation but are often altered in cancer. Less investigated are their pseudogenes. Recently, it was demonstrated that pseudogenes have a key regulatory role in the cell, especially via non-coding RNAs, and that the aberrant expression of ncRNAs has an important role in cancer development and progression. The present review paper, for the first time, collects all that published about the EEFs pseudogenes to create a base for future investigations. For most of them, the studies are in their infancy, while for others the studies suggest their involvement in normal cell physiology but also in various human diseases. However, more investigations are needed to understand their functions in both normal and cancer cells and to define which can be useful biomarkers or therapeutic targets.
Collapse
|
2
|
Mills A, Gago F. On the Need to Tell Apart Fraternal Twins eEF1A1 and eEF1A2, and Their Respective Outfits. Int J Mol Sci 2021; 22:6973. [PMID: 34203525 PMCID: PMC8268798 DOI: 10.3390/ijms22136973] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/25/2021] [Accepted: 06/25/2021] [Indexed: 01/03/2023] Open
Abstract
eEF1A1 and eEF1A2 are paralogous proteins whose presence in most normal eukaryotic cells is mutually exclusive and developmentally regulated. Often described in the scientific literature under the collective name eEF1A, which stands for eukaryotic elongation factor 1A, their best known activity (in a monomeric, GTP-bound conformation) is to bind aminoacyl-tRNAs and deliver them to the A-site of the 80S ribosome. However, both eEF1A1 and eEF1A2 are endowed with multitasking abilities (sometimes performed by homo- and heterodimers) and can be located in different subcellular compartments, from the plasma membrane to the nucleus. Given the high sequence identity of these two sister proteins and the large number of post-translational modifications they can undergo, we are often confronted with the dilemma of discerning which is the particular proteoform that is actually responsible for the ascribed biochemical or cellular effects. We argue in this review that acquiring this knowledge is essential to help clarify, in molecular and structural terms, the mechanistic involvement of these two ancestral and abundant G proteins in a variety of fundamental cellular processes other than translation elongation. Of particular importance for this special issue is the fact that several de novo heterozygous missense mutations in the human EEF1A2 gene are associated with a subset of rare but severe neurological syndromes and cardiomyopathies.
Collapse
Affiliation(s)
| | - Federico Gago
- Department of Biomedical Sciences & “Unidad Asociada IQM-CSIC”, School of Medicine and Health Sciences, University of Alcalá, E-28805 Alcalá de Henares, Spain;
| |
Collapse
|
3
|
Shin W, Wu A, Min S, Shin YC, Fleming RYD, Eckhardt SG, Kim HJ. Spatiotemporal Gradient and Instability of Wnt Induce Heterogeneous Growth and Differentiation of Human Intestinal Organoids. iScience 2020; 23:101372. [PMID: 32745985 PMCID: PMC7398973 DOI: 10.1016/j.isci.2020.101372] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/22/2020] [Accepted: 07/14/2020] [Indexed: 12/12/2022] Open
Abstract
In a conventional culture of three-dimensional human intestinal organoids, extracellular matrix hydrogel has been used to provide a physical space for the growth and morphogenesis of organoids in the presence of exogenous morphogens such as Wnt3a. We found that organoids embedded in a dome-shaped hydrogel show significant size heterogeneity in different locations inside the hydrogel. Computational simulations revealed that the instability and diffusion limitation of Wnt3a constitutively generate a concentration gradient inside the hydrogel. The location-dependent heterogeneity of organoids in a hydrogel dome substantially perturbed the transcriptome profile associated with epithelial functions, cytodifferentiation including mucin 2 expression, and morphological characteristics. This heterogeneous phenotype was significantly mitigated when the Wnt3a was frequently replenished in the culture medium. Our finding suggests that the morphological, transcriptional, translational, and functional heterogeneity in conventional organoid cultures may lead to a false interpretation of the experimental results in organoid-based studies.
Collapse
Affiliation(s)
- Woojung Shin
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W. Dean Keeton St., Austin, TX 78712, USA
| | - Alexander Wu
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W. Dean Keeton St., Austin, TX 78712, USA
| | - Soyoun Min
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W. Dean Keeton St., Austin, TX 78712, USA
| | - Yong Cheol Shin
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W. Dean Keeton St., Austin, TX 78712, USA
| | - R Y Declan Fleming
- Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA; Department of Surgery and Perioperative Care, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA
| | - S Gail Eckhardt
- Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA
| | - Hyun Jung Kim
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W. Dean Keeton St., Austin, TX 78712, USA; Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA; Department of Medical Engineering, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
| |
Collapse
|
4
|
Wu H, Liu M, Zhuang J. Identification of modules of hepatic encephalopathy based on protein-protein network and gene expression data. Exp Ther Med 2018; 15:4344-4348. [PMID: 29849776 PMCID: PMC5962850 DOI: 10.3892/etm.2018.5924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 01/30/2018] [Indexed: 11/06/2022] Open
Abstract
Hepatic encephalopathy (HE) is regarded as a complication of liver cirrhosis, and 50–75% of patients who have been diagnosed with cirrhosis have HE syndrome. The aim of this study was to identify genes and pathways associated with HE alcoholics. Human protein-protein interactions were downloaded from the STRING database. Gene expression data were downloaded from EMBL-EBI. Combined score and Pearson's correlation coefficient were calculated to construct differential co-expression networks. Graph-theoretical measure was used to calculate the module connectivity dynamic score of multiple differential modules. In total, 11,134 genes were obtained after mapping between probes and genes. Then, 501,736 pairs and 16,496 genes were obtained to form background protein-protein interaction networks, 1,435 edges and 460 nodes were obtained constituting differential co-expression networks. Twenty-three seed genes and 10 significantly differential modules were identified. Four significantly differential modules which had larger connectivity alternation were observed. The identified seed genes and significantly differential modules offer novel understanding and molecular targets for the treatment of HE alcoholics.
Collapse
Affiliation(s)
- Hao Wu
- Department of Internal Medicine, Jining Psychiatric Hospital, Jining, Shandong 272051, P.R. China
| | - Miao Liu
- Department of Internal Medicine, Jining Psychiatric Hospital, Jining, Shandong 272051, P.R. China
| | - Jiajun Zhuang
- No. 1 Department of Neurology, Weifang People's Hospital, Weifang, Shandong 261000, P.R. China
| |
Collapse
|
5
|
Characterisation of translation elongation factor eEF1B subunit expression in mammalian cells and tissues and co-localisation with eEF1A2. PLoS One 2014; 9:e114117. [PMID: 25436608 PMCID: PMC4250081 DOI: 10.1371/journal.pone.0114117] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 11/04/2014] [Indexed: 01/15/2023] Open
Abstract
Translation elongation is the stage of protein synthesis in which the translation factor eEF1A plays a pivotal role that is dependent on GTP exchange. In vertebrates, eEF1A can exist as two separately encoded tissue-specific isoforms, eEF1A1, which is almost ubiquitously expressed, and eEF1A2, which is confined to neurons and muscle. The GTP exchange factor for eEF1A1 is a complex called eEF1B made up of subunits eEF1Bα, eEF1Bδ and eEF1Bγ. Previous studies have cast doubt on the ability of eEF1B to interact with eEF1A2, suggesting that this isoform might use a different GTP exchange factor. We show that eEF1B subunits are all widely expressed to varying degrees in different cell lines and tissues, and at different stages of development. We show that ablation of any of the subunits in human cell lines has a small but significant impact on cell viability and cycling. Finally, we show that both eEF1A1 and eEF1A2 colocalise with all eEF1B subunits, in such close proximity that they are highly likely to be in a complex.
Collapse
|
6
|
Structural models of human eEF1A1 and eEF1A2 reveal two distinct surface clusters of sequence variation and potential differences in phosphorylation. PLoS One 2009; 4:e6315. [PMID: 19636410 PMCID: PMC2712093 DOI: 10.1371/journal.pone.0006315] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Accepted: 06/22/2009] [Indexed: 01/27/2023] Open
Abstract
Background Despite sharing 92% sequence identity, paralogous human translation elongation factor 1 alpha-1 (eEF1A1) and elongation factor 1 alpha-2 (eEF1A2) have different but overlapping functional profiles. This may reflect the differential requirements of the cell-types in which they are expressed and is consistent with complex roles for these proteins that extend beyond delivery of tRNA to the ribosome. Methodology/Principal Findings To investigate the structural basis of these functional differences, we created and validated comparative three-dimensional (3-D) models of eEF1A1 and eEF1A2 on the basis of the crystal structure of homologous eEF1A from yeast. The spatial location of amino acid residues that vary between the two proteins was thereby pinpointed, and their surface electrostatic and lipophilic properties were compared. None of the variations amongst buried amino acid residues are judged likely to have a major structural effect on the protein fold, or to affect domain-domain interactions. Nearly all the variant surface-exposed amino acid residues lie on one face of the protein, in two proximal but distinct sub-clusters. The result of previously performed mutagenesis in yeast may be interpreted as confirming the importance of one of these clusters in actin-bundling and filament disorganization. Interestingly, some variant residues lie in close proximity to, and in a few cases show differences in interactions with, residues previously inferred to be directly involved in binding GTP/GDP, eEF1Bα and aminoacyl-tRNA. Additional sequence-based predictions, in conjunction with the 3-D models, reveal likely differences in phosphorylation sites that could reconcile some of the functional differences between the two proteins. Conclusions The revelation and putative functional assignment of two distinct sub-clusters on the surface of the protein models should enable rational site-directed mutagenesis, including homologous reverse-substitution experiments, to map surface binding patches onto these proteins. The predicted variant-specific phosphorylation sites also provide a basis for experimental verification by mutagenesis. The models provide a structural framework for interpretation of the resulting functional analysis.
Collapse
|
7
|
Mansilla F, Dominguez CA, Yeadon JE, Corydon TJ, Burden SJ, Knudsen CR. Translation elongation factor eEF1A binds to a novel myosin binding protein-C-like protein. J Cell Biochem 2008; 105:847-58. [PMID: 18756455 PMCID: PMC2597023 DOI: 10.1002/jcb.21880] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Eukaryotic translation elongation factor 1A (eEF1A) is a guanine-nucleotide binding protein, which transports aminoacylated tRNA to the ribosomal A site during protein synthesis. In a yeast two-hybrid screening of a human skeletal muscle cDNA library, a novel eEF1A binding protein, immunoglobulin-like and fibronectin type III domain containing 1 (IGFN1), was discovered, and its interaction with eEF1A was confirmed in vitro. IGFN1 is specifically expressed in skeletal muscle and presents immunoglobulin I and fibronectin III sets of domains characteristic of sarcomeric proteins. IGFN1 shows sequence and structural homology to myosin binding protein-C fast and slow-type skeletal muscle isoforms. IGFN1 is substantially upregulated during muscle denervation. We propose a model in which this increased expression of IGFN1 serves to down-regulate protein synthesis via interaction with eEF1A during denervation.
Collapse
Affiliation(s)
| | | | - James E. Yeadon
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | | | - Steven J. Burden
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | | |
Collapse
|
8
|
Malone J, Ullrich R. Novel Radiation Response Genes Identified in Gene-Trapped MCF10A Mammary Epithelial Cells. Radiat Res 2007; 167:176-84. [PMID: 17390725 DOI: 10.1667/rr0656.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We have used a gene-trapping strategy to screen human mammary epithelial cells for radiation response genes. Relative mRNA expression levels of five candidate genes in MCF10A cells were analyzed, both with and without exposure to radiation. In all five cases, the trapped genes were significantly down-regulated after radiation treatment. Sequence analysis of the fusion transcripts identified the trapped genes: (1) the human androgen receptor, (2) the uncharacterized DREV1 gene, which has known homology to DNA methyltransferases, (3) the human creatine kinase gene, (4) the human eukaryotic translation elongation factor 1 beta 2, and (5) the human ribosomal protein L27. All five genes were down-regulated significantly after treatment with varying doses of ionizing radiation (0.10 to 4.0 Gy) and at varying times (2-30 h after treatment). The genes were also analyzed in human fibroblast and lymphoblastoid cell lines to determine whether the radiation response being observed was cell-type specific. The results verified that the observed radiation response was not a cell-type-specific phenomenon, suggesting that the genes play essential roles in the radiation damage control pathways. This study demonstrates the potential of the gene-trap approach for the identification and functional analysis of novel radiation response genes.
Collapse
Affiliation(s)
- Jennifer Malone
- Department of Pathology, University of Colorado Health Sciences Center, Aurora, Colorado 80045-0508, USA.
| | | |
Collapse
|
9
|
Carinci F, Piattelli A, Guida L, Perrotti V, Laino G, Oliva A, Annunziata M, Palmieri A, Pezzetti F. Effects of Emdogain on osteoblast gene expression. Oral Dis 2006; 12:329-42. [PMID: 16700745 DOI: 10.1111/j.1601-0825.2005.01204.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Emdogain (EMD) is a protein extract purified from porcine enamel and has been introduced in clinical practice to obtain periodontal regeneration. EMD is composed mainly of amelogenins (90%), while the remaining 10% is composed of non-amelogenin enamel matrix proteins such as enamelins, tuftelin, amelin and ameloblastin. Enamel matrix proteins seem to be involved in root formation. EMD has been reported to promote proliferation, migration, adhesion and differentiation of cells associated with healing periodontal tissues in vivo. DESIGN How this protein acts on osteoblasts is poorly understood. We therefore attempted to address this question by using a microarray technique to identify genes that are differently regulated in osteoblasts exposed to enamel matrix proteins. RESULTS By using DNA microarrays containing 20,000 genes, we identified several upregulated and downregulated genes in the osteoblast-like cell line (MG-63) cultured with enamel matrix proteins (Emd). The differentially expressed genes cover a broad range of functional activities: (i) signaling transduction, (ii) transcription, (iii) translation, (iv) cell cycle regulation, proliferation and apoptosis, (v) immune system, (vi) vesicular transport and lysosome activity, and (vii) cytoskeleton, cell adhesion and extracellular matrix production. CONCLUSIONS The data reported are the first genome-wide scan of the effect of enamel matrix proteins on osteoblast-like cells. These results can contribute to our understanding of the molecular mechanisms of bone regeneration and as a model for comparing other materials with similar clinical effects.
Collapse
Affiliation(s)
- F Carinci
- Department of Maxillofacial Surgery, University of Ferrara, Ferrara, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Le Sourd F, Boulben S, Le Bouffant R, Cormier P, Morales J, Belle R, Mulner-Lorillon O. eEF1B: At the dawn of the 21st century. ACTA ACUST UNITED AC 2006; 1759:13-31. [PMID: 16624425 DOI: 10.1016/j.bbaexp.2006.02.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Revised: 02/21/2006] [Accepted: 02/22/2006] [Indexed: 12/18/2022]
Abstract
Translational regulation of gene expression in eukaryotes can rapidly and accurately control cell activity in response to stimuli or when rapidly dividing. There is increasing evidence for a key role of the elongation step in this process. Elongation factor-1 (eEF1), which is responsible for aminoacyl-tRNA transfer on the ribosome, is comprised of two entities: a G-protein named eEF1A and a nucleotide exchange factor, eEF1B. The multifunctional nature of eEF1A, as well as its oncogenic potential, is currently the subject of a number of studies. Until recently, less work has been done on eEF1B. This review describes the macromolecular complexity of eEF1B, its multiple phosphorylation sites and numerous cellular partners, which lead us to suggest an essential role for the factor in the control of gene expression, particularly during the cell cycle.
Collapse
Affiliation(s)
- Frédéric Le Sourd
- Equipe Cycle Cellulaire et Développement, Unité Mer and Sante, UMR 7150 CNRS/UPMC, Station Biologique de Roscoff, BP 74, 29682 Roscoff Cedex, France
| | | | | | | | | | | | | |
Collapse
|
11
|
Chambers DM, Rouleau GA, Abbott CM. Comparative genomic analysis of genes encoding translation elongation factor 1B(alpha) in human and mouse shows EEF1B1 to be a recent retrotransposition event. Genomics 2001; 77:145-8. [PMID: 11597139 DOI: 10.1006/geno.2001.6626] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have characterized genomic loci encoding translation elongation factor 1B(alpha) (eEF1B(alpha)) in mice and humans. Mice have a single structural locus (named Eef1b2) spanning six exons, which is ubiquitously expressed and maps close to Casp8 on mouse chromosome 1, and a processed pseudogene. Humans have a single intron-containing locus, EEF1B2, which maps to 2q33, and an intronless paralogue expressed only in brain and muscle (EEF1B3). Another locus described previously, EEF1B1, is actually a processed pseudogene on chromosome 15 corresponding to an alternative splice form of EEF1B2. Our study illustrates the value of comparative mapping in distinguishing between processed pseudogenes and intronless paralogues.
Collapse
Affiliation(s)
- D M Chambers
- Medical Genetics Section, Department of Medical Sciences, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | | | | |
Collapse
|
12
|
Hol FA, Schepens MT, van Beersum SE, Redolfi E, Affer M, Vezzoni P, Hamel BC, Karnes PS, Mariman EC, Zucchi I. Identification and characterization of an Xq26-q27 duplication in a family with spina bifida and panhypopituitarism suggests the involvement of two distinct genes. Genomics 2000; 69:174-81. [PMID: 11031100 DOI: 10.1006/geno.2000.6327] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated a family with a duplication, dup(X)q26-q27, that was present in two brothers, their mother, and their maternal grandmother. The brothers carrying the duplication displayed spina bifida and panhypopituitarism, whereas a third healthy brother inherited the normal X chromosome. Preferential inactivation of the X chromosome containing the duplication was evident in healthy carrier females. We determined the boundaries of the Xq26-q27 duplication. Via interphase FISH analysis we narrowed down each of the two breakpoint regions to approximately 300-kb intervals. The proximal breakpoint is located in Xq26.1 between DXS1114 and HPRT and is contained in YAC yWXD599, while the distal breakpoint is located in Xq27.3 between DXS369 and DXS1200 and contained in YAC yWXD758. The duplication comprises about 13 Mb. Evidence from the literature points to a predisposing gene for spina bifida in Xq27. We hypothesize that the spina bifida in the two brothers may be due to interruption of a critical gene in the Xq27 breakpoint region. Several candidate genes were mapped to the Xq27 critical region but none was shown to be disrupted by the duplication event. Recently, M. Lagerström-Fermér et al. (1997, Am. J. Hum. Genet. 60, 910-916) reported on a family with X-linked recessive panhypopituitarism associated with a duplication in Xq26; however, no details were reported on the extent of the duplication. Our study corroborates their hypothesis that X-linked recessive panhypopituitarism is likely to be caused by a gene encoding a dosage-sensitive protein involved in pituitary development. We place the putative gene between DXS1114 and DXS1200, corresponding to the interval defined by the duplication in the present family.
Collapse
Affiliation(s)
- F A Hol
- Department of Human Genetics, University Hospital Nijmegen, Nijmegen, 6500 HB, The Netherlands.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Bévort M, Leffers H. Down regulation of ribosomal protein mRNAs during neuronal differentiation of human NTERA2 cells. Differentiation 2000; 66:81-92. [PMID: 11100899 DOI: 10.1046/j.1432-0436.2000.660203.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have analysed the expression of 32 ribosomal protein (RP) mRNAs during retinoic acid induced neuronal differentiation of human NTERA2 cells. Except for a new S27 variant (S27v), all were down regulated both in selectively replated differentiated neurons and the most differentiated continuous cultures, i.e., non-replated cultures. However, the expression profiles of the individual RP mRNAs were different, most (L3, L7, L8, L10, L13, L23a, L27a, L36a, L39, P0, S2, S3, S3a, S4X, S6, S9, S12, S13, S16, S19, S20, S23, and S27a) exhibited a constant down regulation, whereas a few were either initially constant (L11, L32, S8, and S11) or up regulated (L6, L15, L17, L31, and S27y) and then down regulated. The expression of S27v remained elevated in the most differentiated continuous cultures but was down regulated in replated differentiated neurons. The down regulation of RP mRNAs was variable: the expression levels in differentiated replated neurons were between 10% (S3) and 90% (S11) of the levels in undifferentiated cells. The ratio between rRNA and RP mRNA changed during the differentiation; in differentiated neurons there were, on average, about half the number of RP mRNAs per rRNA as compared to undifferentiated cells. The expression profiles of a few translation-related proteins were also determined. EF1alpha1, EF1beta1, and EF1delta were down regulated, whereas the expression of the neuron and muscle specific EF1alpha2 increased. The reduction in the expression of RP mRNAs was coordinated with a reduction in the expression level of the proliferation marker PCNA. The expression levels of most RP mRNAs were lower in purified differentiated post-mitotic neurons than in the most differentiated continuous cultures, despite similar levels of PCNA, suggesting that both the differentiation state and the proliferative status of the cells affect the expression of RP mRNAs.
Collapse
Affiliation(s)
- M Bévort
- Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark
| | | |
Collapse
|
14
|
Héricourt F, Jupin I. Molecular cloning and characterization of the Arabidopsis thaliana alpha-subunit of elongation factor 1B. FEBS Lett 1999; 464:148-52. [PMID: 10618495 DOI: 10.1016/s0014-5793(99)01694-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Using a PCR-based approach, we have isolated two Arabidopsis thaliana cDNA clones (alpha1 and alpha2) encoding the alpha-subunit of translation elongation factor 1B (eEF1Balpha). They encode open reading frames of 228 and 224 amino acids respectively, with extensive homology to eEF1Balpha subunits from different organisms, particularly in the C-terminal half of the protein. They both lack a conserved phosphorylation site that has been implicated in regulating nucleotide exchange activity. Using a plasmid shuffling experiment, we demonstrated that both alpha1 and alpha2 clones are able to complement a mutant yeast strain deficient for the eEF1Balpha subunit. This provides evidence that Arabidopsis encodes at least two functional isoforms of this subunit, termed eEF1Balpha1 and eEF1Balpha2. A third cDNA clone was isolated that appeared to result from an alternative splicing event of the eEF1Balpha1 gene.
Collapse
Affiliation(s)
- F Héricourt
- Laboratoire de Virologie Moléculaire, Institut Jacques Monod, UMR 7592, CNRS-Universités Paris 6 & Paris 7, 2 place Jussieu, 75251, Paris, France
| | | |
Collapse
|
15
|
Redolfi E, Pizzuti A, Di Bacco A, Susani L, Labella T, Affer M, Montagna C, Reinbold R, Mumm S, Vezzoni P, Zucchi I. Mapping of the MYCL2 processed gene to Xq22-23 and identification of an additional L MYC-related sequence in Xq27.2. FEBS Lett 1999; 446:273-7. [PMID: 10100857 DOI: 10.1016/s0014-5793(99)00243-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We report here the identification of a human genomic sequence from the q27.2 region of the X chromosome which shows a high homology to the L-MYC proto-oncogene. This sequence is not the MYCL2 homology, previously mapped to the long arm of the X chromosome at q22-qter by Morton et al., as we located the MYCL2-processed gene in Xq22-23, using a panel containing a combination of hybrid DNA carrying different portions of the human X chromosome. Based on computer analysis, the MYC-like sequence (MYCL3) is 98.2% identical to a portion of exon 3 of the MYCL1 gene and maps to the Xq27.2 region, between the DXS312 and DXS292 loci.
Collapse
Affiliation(s)
- E Redolfi
- Istituto di Tecnologie Biomediche Avanzate, CNR, Segrate, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Kahns S, Lund A, Kristensen P, Knudsen CR, Clark BF, Cavallius J, Merrick WC. The elongation factor 1 A-2 isoform from rabbit: cloning of the cDNA and characterization of the protein. Nucleic Acids Res 1998; 26:1884-90. [PMID: 9518480 PMCID: PMC147499 DOI: 10.1093/nar/26.8.1884] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic elongation factor 1 A (eEF1A, formerly elongation factor-1 alpha) is an important component of the protein synthesis apparatus. Here we report the isolation and characterization of the cDNA sequence encoding rabbit eEF1A-2, an isoform of eEF1A, as well as a structural and functional comparison of the two rabbit isoforms. Northern analysis of the expression pattern of eEF1A-2 showed that this isoform is expressed in skeletal muscle, heart, brain and aorta, while transcripts are not detected in liver, kidney, spleen and lung. In contrast, the previously characterized eEF1A-1 isoform is expressed in all tissues examined except skeletal muscle. We have recently purified eEF1A-2 from rabbit skeletal muscle. By partial amino acid sequencing and determination of the post-translational modifications of eEF1A-2 we found that both of the glycerylphosphorylethanolamine modifications observed in eEF1A-1 appear to be present in eEF1A-2. However, two of the residues found dimethylated in eEF1A-1 appeared to be trimethylated in eEF1A-2. A comparison of the enzymatic activity showed that eEF1A-1 and eEF1A-2 have indistinguishable activity in an in vitro translation system. In contrast, the GDP dissociation rate constant is approximately 7 times higher for eEF1A-1 than for eEF1A-2. The nucleotide preference ratio (GDP/GTP) for eEF1A-1 was 0.82, while the preference ratio for eEF1A-2 was 1.50.
Collapse
Affiliation(s)
- S Kahns
- Division of Biostructural Chemistry, IMSB, Aarhus University, Gustav Wieds vej 10C, 8000 Arhus C, Denmark
| | | | | | | | | | | | | |
Collapse
|
17
|
Chambers DM, Peters J, Abbott CM. The lethal mutation of the mouse wasted (wst) is a deletion that abolishes expression of a tissue-specific isoform of translation elongation factor 1alpha, encoded by the Eef1a2 gene. Proc Natl Acad Sci U S A 1998; 95:4463-8. [PMID: 9539760 PMCID: PMC22512 DOI: 10.1073/pnas.95.8.4463] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We have identified the mutation responsible for the autosomal recessive wasted (wst) mutation of the mouse. Wasted mice are characterized by wasting and neurological and immunological abnormalities starting at 21 days after birth; they die by 28 days. A deletion of 15.8 kb in wasted mice abolishes expression of a gene called Eef1a2, encoding a protein that is 92% identical at the amino acid level to the translation elongation factor EF1alpha (locus Eef1a). We have found no evidence for the involvement of another gene in this deletion. Expression of Eef1a2 is reciprocal with that of Eef1a. Expression of Eef1a2 takes over from Eef1a in heart and muscle at precisely the time at which the wasted phenotype becomes manifest. These data suggest that there are tissue-specific forms of the translation elongation apparatus essential for postnatal survival in the mouse.
Collapse
Affiliation(s)
- D M Chambers
- Human Genetics Unit, Department of Medicine, University of Edinburgh, Molecular Medicine Centre, Western General Hospital, Edinburgh EH4 2XU, United Kingdom
| | | | | |
Collapse
|
18
|
Lapenta V, Chiurazzi P, van der Spek P, Pizzuti A, Hanaoka F, Brahe C. SMT3A, a human homologue of the S. cerevisiae SMT3 gene, maps to chromosome 21qter and defines a novel gene family. Genomics 1997; 40:362-6. [PMID: 9119407 DOI: 10.1006/geno.1996.4556] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
cDNA selection was used to isolate coding sequences from cosmids mapping to the gene-rich telomeric region of human chromosome 21q. A novel cDNA, termed SMT3A, was isolated and mapped between the loci PFKL and D21S171, about 2.2 Mb proximal to the telomere. The predicted protein of 103 amino acids appears to be a homologue of the Saccharomyces cerevisiae SMT3 protein, whose gene was previously isolated as a suppressor of mutations in the MIF2 gene. The yeast MIF2 gene encodes an essential centromeric protein and shows homology to mammalian CENP-C, an integral component of active kinetochores. SMT3A was found to be highly homologous to two other recently isolated human genes, suggesting the presence of a new gene family. Homologous sequences were also found in protozoa, metazoa, and plants. Moreover, all predicted proteins show significant homology to ubiquitin. The proposed role of yeast SMT3 as centromeric protein and the strong evolutionary conservation of the SMT3A gene suggest an involvement of the encoded protein in the function and/or structure of the eukaryotic kinetochore.
Collapse
Affiliation(s)
- V Lapenta
- Institute of Medical Genetics, Catholic University, Rome, Italy
| | | | | | | | | | | |
Collapse
|
19
|
Levin ML, Chatterjee A, Pragliola A, Worley KC, Wehnert M, Zhuchenko O, Smith RF, Lee CC, Herman GE. A comparative transcription map of the murine bare patches (Bpa) and striated (Str) critical regions and human Xq28. Genome Res 1996; 6:465-77. [PMID: 8828036 DOI: 10.1101/gr.6.6.465] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The X-linked developmental mouse mutations bare patches (Bpa) and striated (Str) may be homologous to human X-linked dominant chondrodysplasia punctata (CDPX2) and incontinentia pigmenti (IP2), respectively, based on their genetic mapping and clinical phenotypes. Bpa and Str have been localized to an overlapping critical region of 600 kb that demonstrates conserved gene order with loci in human Xq28 between DXS1104 and DXS52. As part of efforts to isolate the genes involved in these disorders, we have begun to develop a comparative transcription map spanning this region in both species. Using techniques of cross-species conservation and hybridization, exon trapping, and cDNA selection we have identified four known genes or members of gene families--caltractin, a member of the gamma-aminobutyric acid (GABAA) receptor gene family, a member of the melanoma antigen gene (MAGE) family, and several members of the murine-specific, X-linked lymphocyte regulated gene (Xlr3) family. Trapped exons and, in some cases, longer cDNAs have been isolated for potentially 7-9 additional genes. One cDNA demonstrates highly significant homology with members of the Krüppel family of zinc finger transcription factors. A second novel cDNA demonstrates homology at the 3' end of the predicted amino acid sequence to a LIM domain consensus. Gene order appears conserved among those cDNAs determined to be present in both human and mouse. Three of the murine transcripts appear to be present in multiple copies within the Bpa/Str critical region and could be associated with a predisposition to genomic rearrangements. Reverse transcriptase PCR (RT-PCR) and Northern analysis demonstrate that several of the transcripts are expressed in mid-gestation murine embryos and neonatal skin, making them candidates for the Bpa and Str mutations and their respective homologous human disorders.
Collapse
Affiliation(s)
- M L Levin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | | | | | | | | | | | |
Collapse
|