1
|
Abe N, Imaeda A, Inagaki M, Li Z, Kawaguchi D, Onda K, Nakashima Y, Uchida S, Hashiya F, Kimura Y, Abe H. Complete Chemical Synthesis of Minimal Messenger RNA by Efficient Chemical Capping Reaction. ACS Chem Biol 2022; 17:1308-1314. [PMID: 35608277 DOI: 10.1021/acschembio.1c00996] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Site-specific chemical modification of mRNA can improve its translational efficiency and stability. For this purpose, it is desirable to develop a complete chemical synthesis method for chemically modified mRNA. The key is a chemical reaction that introduces a cap structure into the chemically synthesized RNA. In this study, we developed a fast and quantitative chemical capping reaction between 5'-phosphorylated RNA and N7-methylated GDP imidazolide in the presence of 1-methylimidazole in the organic solvent dimethyl sulfoxide. It enabled quantitative preparation of capping RNA within 3 h. We prepared chemically modified 107-nucleotide mRNAs, including N6-methyladenosine, insertion of non-nucleotide linkers, and 2'-O-methylated nucleotides at the 5' end and evaluated their effects on translational activity in cultured HeLa cells. The results showed that mRNAs with non-nucleotide linkers in the untranslated regions were sufficiently tolerant to translation and that mRNAs with the Cap_2 structure had higher translational activity than those with the Cap_0 structure.
Collapse
Affiliation(s)
- Naoko Abe
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Akihiro Imaeda
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Masahito Inagaki
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Zhenmin Li
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Daisuke Kawaguchi
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Kaoru Onda
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Yuko Nakashima
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Satoshi Uchida
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 1-5 Shimogamohangi-cho, Sakyo-ku, Kyoto 606-0823, Japan
| | - Fumitaka Hashiya
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Yasuaki Kimura
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Hiroshi Abe
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- CREST, Japan Science and Technology Agency, 7 Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan
- Institute for Glyco-core Research (iGCORE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| |
Collapse
|
2
|
Abstract
The Bcl-2 family of proteins regulates mitochondrial outer membrane permeability thereby making life or death decisions for cells. Most of Bcl-2 proteins contain hydrophobic regions that are embedded in intracellular membranes such as mitochondria. These membrane proteins are difficult to express and purify thereby preluding biochemical and biophysical characterizations. Here, we describe a photocrosslinking approach based on in vitro synthesis of Bcl-2 proteins with photoreactive amino acid analogs incorporated at specific locations. These photoreactive proteins are reconstituted into liposomal membranes with defined phospholipids or mitochondrial membranes isolated from animals, and their interactions with other Bcl-2 proteins are detected by photocrosslinking.
Collapse
|
3
|
Cancer Vaccine Immunotherapy with RNA-Loaded Liposomes. Int J Mol Sci 2018; 19:ijms19102890. [PMID: 30249040 PMCID: PMC6213933 DOI: 10.3390/ijms19102890] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/11/2018] [Accepted: 09/12/2018] [Indexed: 12/11/2022] Open
Abstract
Cancer vaccines may be harnessed to incite immunity against poorly immunogenic tumors, however they have failed in therapeutic settings. Poor antigenicity coupled with systemic and intratumoral immune suppression have been significant drawbacks. RNA encoding for tumor associated or specific epitopes can serve as a more immunogenic and expeditious trigger of anti-tumor immunity. RNA stimulates innate immunity through toll like receptor stimulation producing type I interferon, and it mediates potent adaptive responses. Since RNA is inherently unstable, delivery systems have been developed to protect and deliver it to intended targets in vivo. In this review, we discuss liposomes as RNA delivery vehicles and their role as cancer vaccines.
Collapse
|
4
|
Kozak M. Effects of long 5' leader sequences on initiation by eukaryotic ribosomes in vitro. Gene Expr 2018; 1:117-25. [PMID: 1820209 PMCID: PMC5952206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Lengthening the 5' noncoding sequence on SP6-derived transcripts can increase their translational efficiency by an order of magnitude under some conditions of translation in reticulocyte lysates. This effect was observed upon reiterating three different synthetic oligonucleotides, the sequences of which were designed simply to preclude secondary structure. It seems unlikely that such arbitrarily designed sequences are recognized by sequence-specific translational enhancer proteins. Rather, long 5' leader sequences appear to accumulate extra 40S ribosomal subunits, which may account for their translational advantage. The buildup of 40S subunits on long, unstructured leader sequences is predicted by the scanning model for initiation. Leader sequences such as these may be ideal for in vitro expression vectors.
Collapse
Affiliation(s)
- M Kozak
- Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Piscataway 08854
| |
Collapse
|
5
|
Roberts BJ, Johnson KE, McGuinn KP, Saowapa J, Svoboda RA, Mahoney MG, Johnson KR, Wahl JK. Palmitoylation of plakophilin is required for desmosome assembly. J Cell Sci 2014; 127:3782-93. [PMID: 25002405 DOI: 10.1242/jcs.149849] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Desmosomes are prominent adhesive junctions found in various epithelial tissues. The cytoplasmic domains of desmosomal cadherins interact with a host of desmosomal plaque proteins, including plakophilins, plakoglobin and desmoplakin, which, in turn, recruit the intermediate filament cytoskeleton to sites of cell-cell contact. Although the individual components of the desmosome are known, mechanisms regulating the assembly of this junction are poorly understood. Protein palmitoylation is a posttranslational lipid modification that plays an important role in protein trafficking and function. Here, we demonstrate that multiple desmosomal components are palmitoylated in vivo. Pharmacologic inhibition of palmitoylation disrupts desmosome assembly at cell-cell borders. We mapped the site of plakophilin palmitoylation to a conserved cysteine residue present in the armadillo repeat domain. Mutation of this single cysteine residue prevents palmitoylation, disrupts plakophilin incorporation into the desmosomal plaque and prevents plakophilin-dependent desmosome assembly. Finally, plakophilin mutants unable to become palmitoylated act in a dominant-negative manner to disrupt proper localization of endogenous desmosome components and decrease desmosomal adhesion. Taken together, these data demonstrate that palmitoylation of desmosomal components is important for desmosome assembly and adhesion.
Collapse
Affiliation(s)
- Brett J Roberts
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA
| | - Kristen E Johnson
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA
| | - Kathleen P McGuinn
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Jintana Saowapa
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA
| | - Robert A Svoboda
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA
| | - My G Mahoney
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Keith R Johnson
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA Eppley Institute for Research in Cancer and Allied Diseases, Omaha, NE 68198, USA
| | - James K Wahl
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA
| |
Collapse
|
6
|
Törner K, Nakanishi T, Matsuura T, Kato Y, Watanabe H. Optimization of mRNA design for protein expression in the crustacean Daphnia magna. Mol Genet Genomics 2014; 289:707-15. [PMID: 24585253 DOI: 10.1007/s00438-014-0830-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 02/13/2014] [Indexed: 12/01/2022]
Abstract
The water flea Daphnia is a new model organism for ecological, evolutionary, and toxicological genomics. Detailed functional analysis of genes newly discovered through genomic approaches often requires overexpression of the identified protein. In the present study, we report the microinjection of in vitro-synthesized RNAs into the eggs as a method for overexpressing ubiquitous proteins in Daphnia magna. We injected a 1.3-kb mRNA that coded for the red fluorescent protein (DsRed2) flanked by UTRs from the ubiquitously expressed elongation factor 1α-1 (EF1α-1) into D. magna embryos. DsRed2 fluorescence in the embryos was measured 24 h after microinjection. Unexpectedly, the reporter RNA containing the 522-bp full-length EF1α-1 3' UTR failed to induce fluorescence. To assess reporter expression, the length of the 3' UTR that potentially contained negative regulatory elements of protein expression, including AU-rich regions and Musashi binding elements, was serially reduced from the 3' end. Assessing all injected RNA alternatives, mRNA containing the first 60 bp of the 3' UTR gave rise to the highest fluorescence, 14 times the Daphnia auto-fluorescence. In contrast, mRNA lacking the entire 3' UTR hardly induced any change in fluorescence intensity. This is the first evaluation of UTRs of mRNAs delivered into Daphnia embryos by microinjection for overexpressing proteins. The mRNA with truncated 3' UTRs of Daphnia EF1α-1 will be useful not only for gain-of-function analyses but also for labeling proteins and organelles with fluorescent proteins in Daphnia.
Collapse
Affiliation(s)
- Kerstin Törner
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | | | | | | | | |
Collapse
|
7
|
Filchakova O, McIntosh JM. Functional expression of human α9* nicotinic acetylcholine receptors in X. laevis oocytes is dependent on the α9 subunit 5' UTR. PLoS One 2013; 8:e64655. [PMID: 23717646 PMCID: PMC3661583 DOI: 10.1371/journal.pone.0064655] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 04/18/2013] [Indexed: 11/19/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) containing the α9 subunit are expressed in a wide variety of non-neuronal tissues ranging from immune cells to breast carcinomas. The α9 subunit is able to assemble into a functional homomeric nAChR and also co-assemble with the α10 subunit into functional heteromeric nAChRs. Despite the increasing awareness of the important roles of this subunit in vertebrates, the study of human α9-containing nAChRs has been severely limited by difficulties in its expression in heterologous systems. In Xenopus laevis oocytes, functional expression of human α9α10 nAChRs is very low compared to that of rat α9α10 nAChRs. When oocytes were co-injected with cRNA of α9 and α10 subunits of human versus those of rat, oocytes with the rat α9 human α10 combination had an ∼-fold higher level of acetylcholine-gated currents (IACh) than those with the human α9 rat α10 combination, suggesting difficulties with human α9 expression. When the ratio of injected human α9 cRNA to human α10 cRNA was increased from 1∶1 to 5∶1, IACh increased 36-fold (from 142±23 nA to 5171±748 nA). Functional expression of human α9-containing receptors in oocytes was markedly improved by appending the 5′-untranslated region of alfalfa mosaic virus RNA4 to the 5′-leader sequence of the α9 subunit cRNA. This increased the functional expression of homomeric human α9 receptors by 70-fold (from 7±1 nA to 475±158 nA) and of human α9α10 heteromeric receptors by 80-fold (from 113±62 nA to 9192±1137 nA). These findings indicate the importance of the composition of the 5′ untranslated leader sequence for expression of α9-containing nAChRs.
Collapse
Affiliation(s)
- Olena Filchakova
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah, United States of America.
| | | |
Collapse
|
8
|
HER3 targeting of adenovirus by fiber modification increases infection of breast cancer cells in vitro, but not following intratumoral injection in mice. Cancer Gene Ther 2012; 19:888-98. [PMID: 23099884 DOI: 10.1038/cgt.2012.79] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Despite the tremendous potential of adenovirus (Ad) as a delivery vector for cancer gene therapy, its use in clinical settings has been limited, mainly as a result of the limited infectivity in many tumors and the wide tissue tropism associated with Ad. To modify the tropism of the virus, we have inserted the epidermal growth factor-like domain of the human heregulin-α (HRG) into the HI loop of Ad5 fiber. This insertion had no adverse effect on fiber trimerization nor did it affect incorporation of the modified fiber into infectious viral particles. Virions bearing modified fiber displayed growth characteristics and viral yields indistinguishable from those of wild-type (wt) virus. Most importantly, HRG-tagged virions showed enhanced infection of cells expressing the cognate receptors HER3/ErbB3 and HER4/ErbB4. This was significantly reduced in the presence of soluble HRG. Furthermore, HER3-expressing Chinese hamster ovary (CHO) cells were transduced by the HRG-modified virus, but not by wt virus. In contrast, CHO cells expressing the coxsackie-Ad receptor were transduced with both viruses. However, infection of an in vivo breast cancer xenograft model after intratumoral injection was similar with both viruses, suggesting that the tumor microenvironment and/or the route of delivery have important roles in infection of target cells with fiber-modified Ads.
Collapse
|
9
|
Park CH, Lim MS, Rhee YH, Yi SH, Kim BK, Shim JW, Kim YH, Jung SJ, Lee SH. In vitro generation of mature dopamine neurons by decreasing and delaying the expression of exogenous Nurr1. Development 2012; 139:2447-51. [PMID: 22627286 DOI: 10.1242/dev.075978] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neural stem/progenitor cell (NSC/NPC) cultures can be a source of dopamine (DA) neurons for experimental and transplantation purposes. Nurr1, a steroid receptor transcription factor, can overcome the limitations associated with differentiation of cultured NPCs into DA neurons. However, forced Nurr1 expression in NPC cultures generates non-neuronal and/or immature DA cells. We show here that the Nurr1 level and period of expression crucially affect the differentiation and maturation of Nurr1-induced DA neurons. Mature DA neurons were generated by manipulating Nurr1 expression patterns to resemble those in the developing midbrain.
Collapse
Affiliation(s)
- Chang-Hwan Park
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Nebert DW, Gálvez-Peralta M, Hay EB, Li H, Johansson E, Yin C, Wang B, He L, Soleimani M. ZIP14 and ZIP8 zinc/bicarbonate symporters in Xenopus oocytes: characterization of metal uptake and inhibition. Metallomics 2012; 4:1218-25. [DOI: 10.1039/c2mt20177a] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
11
|
Chen SX, Osipovich AB, Ustione A, Potter LA, Hipkens S, Gangula R, Yuan W, Piston DW, Magnuson MA. Quantification of factors influencing fluorescent protein expression using RMCE to generate an allelic series in the ROSA26 locus in mice. Dis Model Mech 2011; 4:537-47. [PMID: 21324933 PMCID: PMC3124063 DOI: 10.1242/dmm.006569] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 12/22/2010] [Indexed: 11/20/2022] Open
Abstract
Fluorescent proteins (FPs) have great utility in identifying specific cell populations and in studying cellular dynamics in the mouse. To quantify the factors that determine both the expression and relative brightness of FPs in mouse embryonic stem cells (mESCs) and in mice, we generated eight different FP-expressing ROSA26 alleles using recombinase-mediated cassette exchange (RMCE). These alleles enabled us to analyze the effects on FP expression of a translational enhancer and different 3'-intronic and/or polyadenylation sequences, as well as the relative brightness of five different FPs, without the confounding position and copy number effects that are typically associated with randomly inserted transgenes. We found that the expression of a given FP can vary threefold or more depending on the genetic features present in the allele. The optimal FP expression cassette contained both a translational enhancer sequence in the 5'-untranslated region (UTR) and an intron-containing rabbit β-globin sequence within the 3'-UTR. The relative expressed brightness of individual FPs varied up to tenfold. Of the five different monomeric FPs tested, Citrine (YFP) was the brightest, followed by Apple, eGFP, Cerulean (CFP) and Cherry. Generation of a line of Cherry-expressing mice showed that there was a 30-fold variation of Cherry expression among different tissues and that there was a punctate expression pattern within cells of all tissues examined. This study should help investigators make better-informed design choices when expressing FPs in mESCs and mice.
Collapse
Affiliation(s)
| | | | - Alessandro Ustione
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0494, USA
| | - Leah A. Potter
- Center for Stem Cell Biology and
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0494, USA
| | | | | | | | - David W. Piston
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0494, USA
| | - Mark A. Magnuson
- Center for Stem Cell Biology and
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0494, USA
| |
Collapse
|
12
|
Liu WX, Liu HL, Chai ZJ, Xu XP, Song YR, Qu LQ. Evaluation of seed storage-protein gene 5' untranslated regions in enhancing gene expression in transgenic rice seed. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2010; 121:1267-74. [PMID: 20563548 DOI: 10.1007/s00122-010-1386-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 06/03/2010] [Indexed: 05/10/2023]
Abstract
5' untranslated regions (UTRs) are important sequence elements that modulate the expression of genes. Using the β-glucuronidase (GUS) reporter gene driven by the GluC promoter for the rice-seed storage-protein glutelin, we evaluated the potential of the 5'-UTRs of six seed storage-protein genes in enhancing the expression levels of the foreign gene in stable transgenic rice lines. All of the 5'-UTRs significantly enhanced the expression level of the GluC promoter without altering its expression pattern. The 5'-UTRs of Glb-1 and GluA-1 increased the expression of GUS by about 3.36- and 3.11-fold, respectively. The two 5'-UTRs downstream of the Glb-1, OsAct2 and CMV35S promoters also increased GUS expression level in stable transgenic rice lines or in transient expression protoplasts. Therefore, the enhancements were independent of the promoter sequence. Real-time quantitative RT-PCR analysis showed that the increase in protein production was not accompanied by alteration in mRNA levels, which suggests that the enhancements were due to increasing the translational efficiencies of the mRNA. The 5'-UTRs of Glb-1 and GluA-1, when combined with strong promoters, might be ideal candidates for high production of recombinant proteins in rice seeds.
Collapse
Affiliation(s)
- Wen Xian Liu
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | | | | | | | | | | |
Collapse
|
13
|
Biyani M, Biyani M, Nemoto N, Ichiki T, Nishigaki K, Husimi Y. Gel shift selection of translation enhancer sequences using messenger RNA display. Anal Biochem 2010; 409:105-11. [PMID: 20950583 DOI: 10.1016/j.ab.2010.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 09/29/2010] [Accepted: 10/06/2010] [Indexed: 12/19/2022]
Abstract
We designed a new approach for selection of translation enhancer sequences that enables efficient protein synthesis in cell-free systems. The selection is based on a gel shift assay of a messenger RNA (mRNA)-protein fusion product that is synthesized in a cell-free translation system using an mRNA display method. A library of randomized 20-nt-long sequences, with all possible combinations of the four nucleotides, upstream of a coding region was screened by successive rounds of screening in which the translation time of the succeeding round was reduced compared with the previous round. An efficient translation enhancer sequence capable of more rapid initiation of cell-free protein synthesis, with a minimal translation time of 5 min, than a natural longer enhancer sequence (Xenopus β-globin 5'UTR) was selected using rabbit reticulocyte extract as a model cell-free translation system. Furthermore, a successful screening of cap-independent translation enhancer sequence and a significant sequence similarity of the selected candidates validated the efficiency of the combined mRNA display and gel shift assay method for the rapid development of advanced cell-free translation systems.
Collapse
Affiliation(s)
- Manish Biyani
- Department of Bioengineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | | | | | | | | | | |
Collapse
|
14
|
Wakiyama M, Kaitsu Y, Matsumoto T, Yokoyama S. Coupled transcription and translation from polymerase chain reaction-amplified DNA in Drosophila Schneider 2 cell-free system. Anal Biochem 2010; 400:142-4. [DOI: 10.1016/j.ab.2010.01.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 01/20/2010] [Accepted: 01/26/2010] [Indexed: 11/15/2022]
|
15
|
Lutz J, Brabeck C, Niemann HH, Kloz U, Korth C, Lingappa VR, Bürkle A. Microdeletions within the hydrophobic core region of cellular prion protein alter its topology and metabolism. Biochem Biophys Res Commun 2010; 393:439-44. [DOI: 10.1016/j.bbrc.2010.02.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Accepted: 02/03/2010] [Indexed: 11/25/2022]
|
16
|
Mie M, Shimizu S, Takahashi F, Kobatake E. Selection of mRNA 5'-untranslated region sequence with high translation efficiency through ribosome display. Biochem Biophys Res Commun 2008; 373:48-52. [PMID: 18544339 DOI: 10.1016/j.bbrc.2008.05.173] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Accepted: 05/27/2008] [Indexed: 10/22/2022]
Abstract
The 5'-untranslated region (5'-UTR) of mRNAs functions as a translation enhancer, promoting translation efficiency. Many in vitro translation systems exhibit a reduced efficiency in protein translation due to decreased translation initiation. The use of a 5'-UTR sequence with high translation efficiency greatly enhances protein production in these systems. In this study, we have developed an in vitro selection system that favors 5'-UTRs with high translation efficiency using a ribosome display technique. A 5'-UTR random library, comprised of 5'-UTRs tagged with a His-tag and Renilla luciferase (R-luc) fusion, were in vitro translated in rabbit reticulocytes. By limiting the translation period, only mRNAs with high translation efficiency were translated. During translation, mRNA, ribosome and translated R-luc with His-tag formed ternary complexes. They were collected with translated His-tag using Ni-particles. Extracted mRNA from ternary complex was amplified using RT-PCR and sequenced. Finally, 5'-UTR with high translation efficiency was obtained from random 5'-UTR library.
Collapse
Affiliation(s)
- Masayasu Mie
- Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, B-28 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8501, Japan
| | | | | | | |
Collapse
|
17
|
Iizuka M, Tomita M, Shimizu K, Kikuchi Y, Yoshizato K. Translational enhancement of recombinant protein synthesis in transgenic silkworms by a 5′-untranslated region of polyhedrin gene of Bombyx mori Nucleopolyhedrovirus. J Biosci Bioeng 2008; 105:595-603. [DOI: 10.1263/jbb.105.595] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 02/27/2008] [Indexed: 11/17/2022]
|
18
|
Hino M, Kataoka M, Kajimoto K, Yamamoto T, Kido JI, Shinohara Y, Baba Y. Efficiency of cell-free protein synthesis based on a crude cell extract from Escherichia coli, wheat germ, and rabbit reticulocytes. J Biotechnol 2007; 133:183-9. [PMID: 17826860 DOI: 10.1016/j.jbiotec.2007.08.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 07/05/2007] [Accepted: 08/01/2007] [Indexed: 11/18/2022]
Abstract
The efficiency of protein synthesis for glyceraldehyde-3-phosphate dehydrogenase (G3PDH) was examined with several in vitro coupled transcription/translation protein synthesis systems based on Escherichia coli lysate, wheat germ, or reticulocyte lysate, and an in vitro translation system based on wheat germ extract. A significant amount of protein synthesis was observed only in systems based on E. coli using pET/G3PDH as the expression vector. A remarkable increase of protein synthesis was obtained in wheat germ using a pT(N)T expression vector which contains a 5'-globin leader sequence and a synthetic poly(A)(30) tail instead of pET. A significant difference of T7 RNA polymerase presence by Western blot analysis was not observed in the first four systems, and the difference of total RNA presence in each reaction mixture by Northern blot analysis seemed unrelated to protein synthesis. Although a small amount of protein was synthesized using RNA-encoding G3PDH transcribed in vitro with pET/G3PDH by an in vitro translation system, an extreme increase was observed using transcribed RNA with pEU/G3PDH, which contains T7 RNA promoter and a translation enhancer, Omega sequence. These results suggest that the presence of an enhancer sequence for translation is one of the critical steps for protein synthesis by a eukaryotic cell-free protein synthesis system.
Collapse
Affiliation(s)
- Mami Hino
- Biomarker Analysis Team, Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Japan
| | | | | | | | | | | | | |
Collapse
|
19
|
Theisen CS, Wahl JK, Johnson KR, Wheelock MJ. NHERF links the N-cadherin/catenin complex to the platelet-derived growth factor receptor to modulate the actin cytoskeleton and regulate cell motility. Mol Biol Cell 2007; 18:1220-32. [PMID: 17229887 PMCID: PMC1838972 DOI: 10.1091/mbc.e06-10-0960] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Using phage display, we identified Na+/H+ exchanger regulatory factor (NHERF)-2 as a novel binding partner for the cadherin-associated protein, beta-catenin. We showed that the second of two PSD-95/Dlg/ZO-1 (PDZ) domains of NHERF interacts with a PDZ-binding motif at the very carboxy terminus of beta-catenin. N-cadherin expression has been shown to induce motility in a number of cell types. The first PDZ domain of NHERF is known to bind platelet-derived growth factor-receptor beta (PDGF-Rbeta), and the interaction of PDGF-Rbeta with NHERF leads to enhanced cell spreading and motility. Here we show that beta-catenin and N-cadherin are in a complex with NHERF and PDGF-Rbeta at membrane ruffles in the highly invasive fibrosarcoma cell line HT1080. Using a stable short hairpin RNA system, we showed that HT1080 cells knocked down for either N-cadherin or NHERF had impaired ability to migrate into the wounded area in a scratch assay, similar to cells treated with a PDGF-R kinase inhibitor. Cells expressing a mutant NHERF that is unable to associate with beta-catenin had increased stress fibers, reduced lamellipodia, and impaired cell migration. Using HeLa cells, which express little to no PDGF-R, we introduced PDGF-Rbeta and showed that it coimmunoprecipitates with N-cadherin and that PDGF-dependent cell migration was reduced in these cells when we knocked-down expression of N-cadherin or NHERF. These studies implicate N-cadherin and beta-catenin in cell migration via PDGF-R-mediated signaling through the scaffolding molecule NHERF.
Collapse
Affiliation(s)
- Christopher S. Theisen
- Department of Biochemistry and Molecular Biology, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-7696
| | - James K. Wahl
- Department of Biochemistry and Molecular Biology, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-7696
| | - Keith R. Johnson
- Department of Biochemistry and Molecular Biology, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-7696
| | - Margaret J. Wheelock
- Department of Biochemistry and Molecular Biology, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-7696
| |
Collapse
|
20
|
Maeda M, Johnson E, Mandal SH, Lawson KR, Keim SA, Svoboda RA, Caplan S, Wahl JK, Wheelock MJ, Johnson KR. Expression of inappropriate cadherins by epithelial tumor cells promotes endocytosis and degradation of E-cadherin via competition for p120(ctn). Oncogene 2006; 25:4595-604. [PMID: 16786001 DOI: 10.1038/sj.onc.1209396] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cadherin cell-cell adhesion proteins play an important role in modulating the behavior of tumor cells. E-cadherin serves as a suppressor of tumor cell invasion, and when tumor cells turn on the expression of a non-epithelial cadherin, they often express less E-cadherin, enhancing the tumorigenic phenotype of the cells. Here, we show that when A431 cells are forced to express R-cadherin, they dramatically downregulate the expression of endogenous E- and P-cadherin. In addition, we show that this downregulation is owing to increased turnover of the endogenous cadherins via clathrin-dependent endocytosis. p120(ctn) binds to the juxtamembrane domain of classical cadherins and has been proposed to regulate cadherin adhesive activity. One way p120(ctn) may accomplish this is to serve as a rheostat to regulate the levels of cadherin. Here, we show that the degradation of E-cadherin in response to expression of R-cadherin is owing to competition for p120(ctn).
Collapse
Affiliation(s)
- M Maeda
- Department of Oral Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Conway G, Torrejón M, Lin S, Reinsch S. Fluorescent tagged analysis of neural gene function using mosaics in zebrafish and Xenopus laevis. Brain Res 2006; 1070:150-9. [PMID: 16430873 DOI: 10.1016/j.brainres.2005.11.079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Revised: 11/13/2005] [Accepted: 11/25/2005] [Indexed: 10/25/2022]
Abstract
An important question in the neurosciences is the role of specific gene expression in the control of neural morphology and connectivity. To address this question, methods are needed for expression of exogenous genes in a subset of neurons. This limited and mosaic expression allows the assessment of gene expression in a cell autonomous fashion without environmental contributions from neighboring expressing cells. These methods must also label neurons so that detailed morphology and neural connections can be evaluated. The labeling method should label only a subset of neurons so that neuronal morphology can be viewed upon a non-stained background, in a Golgi staining fashion. Here, we report methods using plasmids called pTAGUM (tagged analysis of genes using mosaics) that accomplish these goals. These methods should prove useful for the analysis of neural gene function in two important model organisms, the zebrafish and Xenopus laevis.
Collapse
Affiliation(s)
- Greg Conway
- NASA Ames Research Center, Moffett Field, CA 94035, USA.
| | | | | | | |
Collapse
|
22
|
Gudkov AT, Ozerova MV, Shiryaev VM, Spirin AS. 5'-poly(A) sequence as an effective leader for translation in eukaryotic cell-free systems. Biotechnol Bioeng 2005; 91:468-73. [PMID: 15986488 DOI: 10.1002/bit.20525] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Poly(A) sequence of 25 adenylic residues placed immediately before the start codons of the green fluorescent protein (GFP) and firefly luciferase (Luc) mRNAs is shown to provide a high rate of translation of the heterologous messages in eukaryotic cell-free translation systems. Also the poly(A) leader is found to provide the abolition of the inhibition of translation at excess mRNA concentrations. The possibility of the practical use of the constructs with the poly(A) leader for preparative protein production is demonstrated in the wheat germ continuous-exchange cell-free (CECF) translation system.
Collapse
Affiliation(s)
- Anatoly T Gudkov
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
| | | | | | | |
Collapse
|
23
|
Hwang YT, Pelitire SM, Henderson MPA, Andrews DW, Dyer JM, Mullen RT. Novel targeting signals mediate the sorting of different isoforms of the tail-anchored membrane protein cytochrome b5 to either endoplasmic reticulum or mitochondria. THE PLANT CELL 2004; 16:3002-19. [PMID: 15486098 PMCID: PMC527194 DOI: 10.1105/tpc.104.026039] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Accepted: 08/26/2004] [Indexed: 05/20/2023]
Abstract
Tail-anchored membrane proteins are a class of proteins that are targeted posttranslationally to various organelles and integrated by a single segment of hydrophobic amino acids located near the C terminus. Although the localization of tail-anchored proteins in specific subcellular compartments in plant cells is essential for their biological function, the molecular targeting signals responsible for sorting these proteins are not well defined. Here, we describe the biogenesis of four closely related tung (Aleurites fordii) cytochrome b5 isoforms (Cb5-A, -B, -C, and -D), which are small tail-anchored proteins that play an essential role in many cellular processes, including lipid biosynthesis. Using a combination of in vivo and in vitro assays, we show that Cb5-A, -B, and -C are targeted exclusively to the endoplasmic reticulum (ER), whereas Cb5-D is targeted specifically to mitochondrial outer membranes. Comprehensive mutational analyses of ER and mitochondrial Cb5s revealed that their C termini, including transmembrane domains (TMD) and tail regions, contained several unique physicochemical and sequence-specific characteristics that defined organelle-specific targeting motifs. Mitochondrial targeting of Cb5 was mediated by a combination of hydrophilic amino acids along one face of the TMD, an enrichment of branched beta-carbon-containing residues in the medial portion of the TMD, and a dibasic -R-R/K/H-x motif in the C-terminal tail. By contrast, ER targeting of Cb5 depended primarily upon the overall length and hydrophobicity of the TMD, although an -R/H-x-Y/F- motif in the tail was also a targeting determinant. Collectively, the results presented provide significant insight into the early biogenetic events required for entry of tail-anchored proteins into either the ER or mitochondrial targeting pathways.
Collapse
Affiliation(s)
- Yeen Ting Hwang
- Department of Botany, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | | | | | | | | | | |
Collapse
|
24
|
Johnson E, Theisen CS, Johnson KR, Wheelock MJ. R-cadherin influences cell motility via Rho family GTPases. J Biol Chem 2004; 279:31041-9. [PMID: 15143071 DOI: 10.1074/jbc.m400024200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Classical cadherins are the transmembrane proteins of the adherens junction and mediate cell-cell adhesion via homotypic interactions in the extracellular space. In addition, they mediate connections to the cytoskeleton by means of their association with catenins. Decreased cadherin-mediated adhesion has been implicated as an important component of tumorigenesis. Cadherin switching is central to the epithelial to mesenchymal transitions that drive normal developmental processes. Cadherin switching has also been implicated in tumorigenesis, particularly in metastasis. Recently, cadherins have been shown to be engaged in cellular activities other than adhesion, including motility, invasion, and signaling. In this study, we show that inappropriate expression of R-cadherin in tumor cells results in decreased expression of endogenous cadherins (cadherin switching) and sustained signaling through Rho GTPases. In addition, we show that R-cadherin induces cell motility when expressed in epithelial cells and that this increased motility is dependent upon Rho GTPase activity.
Collapse
Affiliation(s)
- Emhonta Johnson
- Department of Oral Biology, College of Dentistry, Eppley Institute for Research in Cancer and Allied Diseases, and Eppley Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA
| | | | | | | |
Collapse
|
25
|
Van Eden ME, Byrd MP, Sherrill KW, Lloyd RE. Demonstrating internal ribosome entry sites in eukaryotic mRNAs using stringent RNA test procedures. RNA (NEW YORK, N.Y.) 2004; 10:720-30. [PMID: 15037781 PMCID: PMC1370562 DOI: 10.1261/rna.5225204] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Accepted: 01/13/2004] [Indexed: 05/18/2023]
Abstract
The dicistronic assay for internal ribosome entry site (IRES) activity is the most widely used method for testing putative sequences that may drive cap-independent translation initiation. This assay typically involves the transfection of cells with dicistronic DNA test constructs. Many of the reports describing eukaryotic IRES elements have been criticized for the use of inadequate methods for the detection of aberrant RNAs that may form in transfected cells using this assay. Here we propose the combined use of a new RNAi-based method together with RT-PCR to effectively identify aberrant RNAs. We illustrate the use of these methods for analysis of RNAs generated in cells transfected with dicistronic test DNAs containing either the hepatitis C virus (HCV) IRES or the X-linked inhibitor of apoptosis (XIAP) cellular IRES. Both analyses indicated aberrantly spliced transcripts occurred in cells transfected with the XIAP dicistronic DNA construct. This contributed to the unusually high levels of apparent IRES activity exhibited by the XIAP 5' UTR in vivo. Cells transfected directly with dicistronic RNA exhibited much lower levels of XIAP IRES activity, resembling the lower levels observed after translation of dicistronic RNA in rabbit reticulocyte lysates. No aberrantly spliced transcripts could be detected following direct RNA transfection of cells. Interestingly, transfection of dicistronic DNA or RNA containing the HCV IRES did not form aberrantly spliced transcripts. These observations stress the importance of using alternative test procedures (e.g., direct RNA transfection) in conjunction with a combination of sensitive RNA analyses for discerning IRES-containing sequences in eukaryotic mRNAs.
Collapse
Affiliation(s)
- Marc E Van Eden
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030-3498, USA
| | | | | | | |
Collapse
|
26
|
McCartney AW, Dyer JM, Dhanoa PK, Kim PK, Andrews DW, McNew JA, Mullen RT. Membrane-bound fatty acid desaturases are inserted co-translationally into the ER and contain different ER retrieval motifs at their carboxy termini. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 37:156-173. [PMID: 14690501 DOI: 10.1111/j.1365-313x.2004.01949.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fatty acid desaturases (FADs) play a prominent role in plant lipid metabolism and are located in various subcellular compartments, including the endoplasmic reticulum (ER). To investigate the biogenesis of ER-localized membrane-bound FADs, we characterized the mechanisms responsible for insertion of Arabidopsis FAD2 and Brassica FAD3 into ER membranes and determined the molecular signals that maintain their ER residency. Using in vitro transcription/translation reactions with ER-derived microsomes, we show that both FAD2 and FAD3 are efficiently integrated into membranes by a co-translational, translocon-mediated pathway. We also demonstrate that while the C-terminus of FAD3 (-KSKIN) contains a functional prototypic dilysine ER retrieval motif, FAD2 contains a novel C-terminal aromatic amino acid-containing sequence (-YNNKL) that is both necessary and sufficient for maintaining localization in the ER. Co-expression of a membrane-bound reporter protein containing the FAD2 C-terminus with a dominant-negative mutant of ADP-ribosylation factor (Arf)1 abolished transient localization of the reporter protein in the Golgi, indicating that the FAD2 peptide signal acts as an ER retrieval motif. Mutational analysis of the FAD2 ER retrieval signal revealed a sequence-specific motif consisting of Phi-X-X-K/R/D/E-Phi-COOH, where -Phi- are large hydrophobic amino acid residues. Interestingly, this aromatic motif was present in a variety of other known and putative ER membrane proteins, including cytochrome P450 and the peroxisomal biogenesis factor Pex10p. Taken together, these data describe the insertion and retrieval mechanisms of FADs and define a new ER localization signal in plants that is responsible for the retrieval of escaped membrane proteins back to the ER.
Collapse
|
27
|
Katafiasz BJ, Nieman MT, Wheelock MJ, Johnson KR. Characterization of cadherin-24, a novel alternatively spliced type II cadherin. J Biol Chem 2003; 278:27513-9. [PMID: 12734196 DOI: 10.1074/jbc.m304119200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cadherins comprise a superfamily of calcium-dependent cell-cell adhesion molecules. Within the superfamily are six subfamilies including type I and type II cadherins. Both type I and type II cadherins are composed of five extracellular repeat domains with conserved calcium-binding motifs, a single pass transmembrane domain, and a highly conserved cytoplasmic domain that interacts with beta-catenin and p120 catenin. In this study, we describe a novel cadherin, cadherin-24. It is a type II cadherin with a 781-codon open reading frame, which encodes a type II cadherin protein complete with five extracellular repeats containing calcium-binding motifs, a transmembrane domain, and a conserved cytoplasmic domain. Cadherin-24 has the unusual feature of being alternatively spliced in extracellular repeat 4. This alternative exon encodes 38 in-frame amino acids, resulting in an 819-amino-acid protein. Sequence analysis suggests the presence of beta-catenin and p120 catenin-binding sequences, and immunoprecipitation experiments confirm the ability of both forms of the novel cadherin to associate with alpha-catenin, beta-catenin, and p120 catenin. In addition, aggregation assays show that both forms of cadherin-24 mediate strong cell-cell adhesion.
Collapse
Affiliation(s)
- Bryan J Katafiasz
- University of Nebraska Medical Center, Department of Oral Biology, College of Dentistry and Eppley Cancer Center, Omaha, Nebraska 68198, USA
| | | | | | | |
Collapse
|
28
|
Flanagan JJ, Chen JC, Miao Y, Shao Y, Lin J, Bock PE, Johnson AE. Signal recognition particle binds to ribosome-bound signal sequences with fluorescence-detected subnanomolar affinity that does not diminish as the nascent chain lengthens. J Biol Chem 2003; 278:18628-37. [PMID: 12621052 DOI: 10.1074/jbc.m300173200] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The binding of signal recognition particle (SRP) to ribosome-bound signal sequences has been characterized directly and quantitatively using fluorescence spectroscopy. A fluorescent probe was incorporated cotranslationally into the signal sequence of a ribosome.nascent chain complex (RNC), and upon titration with SRP, a large and saturable increase in fluorescence intensity was observed. Spectral analyses of SRP and RNC association as a function of concentration allowed us to measure, at equilibrium, K(d) values of 0.05-0.38 nm for SRP.RNC complexes with different signal sequences. Competitive binding experiments with nonfluorescent RNC species revealed that the nascent chain probe did not alter SRP affinity and that SRP has significant affinity for both nontranslating ribosomes (K(d) = 71 nm) and RNCs that lack an exposed signal sequence (K(d) = 8 nm). SRP can therefore distinguish between translating and nontranslating ribosomes. The very high signal sequence-dependent SRP.RNC affinity did not decrease as the nascent chain lengthened. Thus, the inhibition of SRP-dependent targeting of RNCs to the endoplasmic reticulum membrane observed with long nascent chains does not result from reduced SRP binding to the signal sequence, as widely thought, but rather from a subsequent step, presumably nascent chain interference of SRP.RNC association with the SRP receptor and/or translocon.
Collapse
Affiliation(s)
- John J Flanagan
- Department of Medical Biochemistry and Genetics, Health Science Center, Texas A&M University, College Station, Texas 77843, USA
| | | | | | | | | | | | | |
Collapse
|
29
|
Affiliation(s)
- J R Smiley
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | | | | |
Collapse
|
30
|
Rose SD, Swift GH, Peyton MJ, Hammer RE, MacDonald RJ. The role of PTF1-P48 in pancreatic acinar gene expression. J Biol Chem 2001; 276:44018-26. [PMID: 11562365 DOI: 10.1074/jbc.m106264200] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 100-base pair ELA1 transcriptional enhancer drives high level transcription to pancreatic acinar cells of transgenic mice and in transfected pancreatic acinar cells in culture. The A element within the enhancer is the sole positively acting element for acinar specificity. We show that the acinar cell-specific bHLH protein PTF1-P48 and the common bHLH cofactor HEB are part of the PTF1 complex that binds the A element and mediates its activity. Acinar-like activity of the enhancer can be reconstituted in HeLa cells by the introduction of P48, HEB, and the PDX1-containing trimeric homeodomain complex that binds the second pancreatic element of the enhancer. The 5' region of the mouse Ptf1-p48 gene from -12.5 to +0.2 kilobase pairs contains the regulatory information to direct expression in transgenic mice to the pancreas and other organs of the gut that express the endogenous Ptf1-p48 gene. The 5'-flanking sequence contains two activating regions, one of which is specific for acinar cells, and a repressing domain active in non-pancreatic cells. Comparison of the 5'-gene flanking regions of the mouse, rat, and human genes identified conserved sequence blocks containing binding sites for known gut transcription factors within the acinar cell-specific control region.
Collapse
Affiliation(s)
- S D Rose
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA
| | | | | | | | | |
Collapse
|
31
|
Hanes J, Jermutus L, Plückthun A. Selecting and evolving functional proteins in vitro by ribosome display. Methods Enzymol 2001; 328:404-30. [PMID: 11075357 DOI: 10.1016/s0076-6879(00)28409-7] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- J Hanes
- Department of Biochemistry, University of Zurich, Switzerland
| | | | | |
Collapse
|
32
|
Védie B, Jeunemaitre X, Mégnien JL, Atger V, Simon A, Moatti N. A new DNA polymorphism in the 5' untranslated region of the human SREBP-1a is related to development of atherosclerosis in high cardiovascular risk population. Atherosclerosis 2001; 154:589-97. [PMID: 11257259 DOI: 10.1016/s0021-9150(00)00569-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Sterol-regulatory element binding proteins (SREBPs) are ubiquitous transcription factors that regulate the genes encoding key proteins in the control of cholesterol homeostasis. We looked for mutations or polymorphisms within the sequences of the SREBP-1a gene critical for the synthesis and/or activity of the protein in 204 asymptomatic men. A single G deletion at base pair -36 of the translation initiation site (designated G-) was found using single-strand conformation polymorphism (SSCP), in addition to three rare variants. This new marker was then assessed for its influence on the lipid parameters of 812 men at high cardiovascular risk, and on the presence of echographic atherosclerotic plaque in their peripheral arteries. The allelic frequency of the -36delG polymorphism was 0.58. At least one plaque was found in the carotid in 24% of subjects, in the femoral arteries of 48%, and in the aorta of 25%. There were significant associations between the -36delG polymorphism and mean total cholesterol (p=0.02) and LDL-cholesterol (P=0.02). There was a graded relationship between the G- allele and the presence of carotid plaque (r=0.084, P=0.02). In addition, there was a statistically significant interaction between the -36delG genotype and the apoE phenotype for plasma LDL-cholesterol (P=0.04) and apoB (P=0.05), suggesting a gene-gene interaction. Stepwise multiple regression analysis for lipid traits, risk factors, and apoE phenotype showed an independent association between carotid plaque and the -36delG polymorphism (beta=0.311, P=0.03). Thus, we have identified a new polymorphism in the 5' untranslated region of the SREBP-1a gene, and demonstrated its association with an atherogenic lipid profile and echographic plaques.
Collapse
Affiliation(s)
- B Védie
- Laboratoire de Biochimie Appliquée, Faculté des Sciences Pharmaceutiques et Biologiques, Châtenay-Malabry, France.
| | | | | | | | | | | |
Collapse
|
33
|
Kim JB, Islam S, Kim YJ, Prudoff RS, Sass KM, Wheelock MJ, Johnson KR. N-Cadherin extracellular repeat 4 mediates epithelial to mesenchymal transition and increased motility. J Cell Biol 2000; 151:1193-206. [PMID: 11121435 PMCID: PMC2190584 DOI: 10.1083/jcb.151.6.1193] [Citation(s) in RCA: 166] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2000] [Accepted: 10/12/2000] [Indexed: 12/05/2022] Open
Abstract
E- and N-cadherin are members of the classical cadherin family of proteins. E-cadherin plays an important role in maintaining the normal phenotype of epithelial cells. Previous studies from our laboratory and other laboratories have shown that inappropriate expression of N-cadherin by tumor cells derived from epithelial tissue results in conversion of the cell to a more fibroblast-like cell, with increased motility and invasion. Our present study was designed to determine which domains of N-cadherin make it different from E-cadherin, with respect to altering cellular behavior, such as which domains are responsible for the epithelial to mesenchymal transition and increased cell motility and invasion. To address this question, we constructed chimeric cadherins comprised of selected domains of E- and N-cadherin. The chimeras were transfected into epithelial cells to determine their effect on cell morphology and cellular behavior. We found that a 69-amino acid portion of EC-4 of N-cadherin was necessary and sufficient to promote both an epithelial to mesenchymal transition in squamous epithelial cells and increased cell motility. Here, we show that different cadherin family members promote different cellular behaviors. In addition, we identify a novel activity that can be ascribed to the extracellular domain of N-cadherin.
Collapse
Affiliation(s)
- Jae-Beom Kim
- Department of Biology, University of Toledo, Toledo, Ohio 43606
| | - Shahidul Islam
- Department of Biology, University of Toledo, Toledo, Ohio 43606
| | - Young J. Kim
- Department of Biology, University of Toledo, Toledo, Ohio 43606
| | - Ryan S. Prudoff
- Department of Biology, University of Toledo, Toledo, Ohio 43606
| | - Kristin M. Sass
- Department of Biology, University of Toledo, Toledo, Ohio 43606
| | | | | |
Collapse
|
34
|
Nucleotide-dependent Binding of the GTPase Domain of the Signal Recognition Particle Receptor β-Subunit to the α-Subunit. J Biol Chem 2000. [DOI: 10.1016/s0021-9258(19)61528-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
35
|
Nieset JE, Sacco-Bubulya PA, Sadler TM, Johnson KR, Wheelock MJ. The amino- and carboxyl-terminal tails of (beta)-catenin reduce its affinity for desmoglein 2. J Cell Sci 2000; 113 ( Pt 10):1737-45. [PMID: 10769205 DOI: 10.1242/jcs.113.10.1737] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
beta-catenin and plakoglobin are members of the armadillo family of proteins and were first identified as components of intercellular adhering junctions. In the adherens junction beta-catenin and plakoglobin serve to link classical cadherins to the actin-based cytoskeleton. In the desmosome plakoglobin links the desmosomal cadherins, the desmogleins and the desmocollins, to the intermediate filament cytoskeleton. beta-catenin is not a component of the desmosome. Previously we have shown that the central armadillo repeat region of plakoglobin is the site for desmosomal cadherin binding. We hypothesized that the unique amino- and/or carboxyl-terminal ends of beta-catenin may regulate its exclusion from the desmosomal plaque. To test this hypothesis we used chimeras between beta-catenin and plakoglobin to identify domain(s) that modulate association with desmoglein 2. Chimeric constructs, each capable of associating with classical cadherins, were assayed for association with the desmosomal cadherin desmoglein 2. Addition of either the N- or C-terminal tail of beta-catenin to the armadillo repeats of plakoglobin did not interfere with desmoglein 2 association. However, when both beta-catenin amino terminus and carboxyl terminus were added to the plakoglobin armadillo repeats, association with desmoglein 2 was diminished. Removal of the first 26 amino acids from this construct restored association. We show evidence for direct protein-protein interactions between the amino- and carboxyl-terminal tails of beta-catenin and propose that a sequence in the first 26 amino acids of beta-catenin along with its carboxyl-terminal tail decrease its affinity for desmoglein and prevent its inclusion in the desmosome.
Collapse
|
36
|
Kim PK, Hollerbach C, Trimble WS, Leber B, Andrews DW. Identification of the endoplasmic reticulum targeting signal in vesicle-associated membrane proteins. J Biol Chem 1999; 274:36876-82. [PMID: 10601239 DOI: 10.1074/jbc.274.52.36876] [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: 11/06/2022] Open
Abstract
The vesicle-associated membrane proteins (Vamp(s)) function as soluble N-ethylmaleimide-sensitive factor attachment receptor proteins in the intracellular trafficking of vesicles. The membrane attachment of Vamps requires a carboxyl-terminal hydrophobic sequence termed an insertion sequence. Unlike other insertion sequence-containing proteins, targeting of the highly homologous Vamp1 and Vamp2 to the endoplasmic reticulum requires ATP and a membrane-bound receptor. To determine if this mechanism of targeting to the endoplasmic reticulum extends to other Vamps, we compared the membrane binding of Vamp1 and Vamp2 with the distantly related Vamp8. Similar to the other Vamps, Vamp8 requires both ATP and a membrane component to target to the endoplasmic reticulum. Furthermore, binding curves for the three Vamps overlap, suggesting a common receptor-mediated process. We identified a minimal endoplasmic reticulum targeting domain that is both necessary and sufficient to confer receptor-mediated, ATP-dependent, binding of a heterologous protein to microsomes. Surprisingly, this conserved sequence includes four positively charged amino acids spaced along an amphipathic sequence, which unlike the carboxyl-terminal targeting sequence in mitochondrial Vamp isoforms, is amino-terminal to the insertion sequence. Because Vamps do not bind to phospholipid vesicles, it is likely that these residues mediate an interaction with a protein, rather than bind to acidic phospholipids. Therefore, we suggest that a bipartite motif is required for the specific targeting and integration of Vamps into the endoplasmic reticulum with receptor-mediated recognition of specifically configured positive residues leading to the insertion of the hydrophobic tail into the membrane.
Collapse
Affiliation(s)
- P K Kim
- Department of Biochemistry, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | | | | | | | | |
Collapse
|
37
|
Ho PJ, Sloane-Stanley J, Athanassiadou A, Wood WG, Thein SL. An in vitro system for expression analysis of mutations of the beta-globin gene: validation and application to two mutations in the 5' UTR. Br J Haematol 1999; 106:938-47. [PMID: 10519995 DOI: 10.1046/j.1365-2141.1999.01659.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We describe the setting up of an in vitro expression system for the analysis of mutations of the beta-globin gene. The system is based on the stable transfection of a normal or mutated beta-globin gene into mouse erythroleukaemia (MEL) cells. The expression construct contains an Agamma gene as an internal control and both globin genes are under the control of the HS2 element of the beta LCR. The system enables analysis of transcription, RNA processing and transport, as well as mRNA stability. With non-mutant genes, high-level expression of both beta and Agamma genes is seen and both mRNAs are stable. The system was validated by comparing the expression of the beta654 thalassaemia splicing mutation in MEL cells with its well-characterized expression in vivo. The level of the initial transcript, the proportion of abnormally spliced mRNA and its instability during erythroid cell maturation were all faithfully reproduced. The system was used to examine the mechanism by which two mutations in the beta-globin 5' untranslated region (5' UTR) result in beta thalassaemia. Surprisingly, the mechanism appeared to differ in the two cases, with the C-G substitution at position +33 affecting transcription, whereas the -T deletion at position +10 resulted in a translational defect. The stably transfected MEL cells, with an internal control and an endogenous enhancer, appear to be a valid and realistic experimental model, superior to transient expression studies. This system should find wide application in the analysis of the effects and mechanisms of gene inactivation in mutations affecting the beta-globin as well as other genes.
Collapse
Affiliation(s)
- P J Ho
- MRC Molecular Haematology Unit, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford.
| | | | | | | | | |
Collapse
|
38
|
Nieman MT, Kim JB, Johnson KR, Wheelock MJ. Mechanism of extracellular domain-deleted dominant negative cadherins. J Cell Sci 1999; 112 ( Pt 10):1621-32. [PMID: 10212155 DOI: 10.1242/jcs.112.10.1621] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cadherin/catenin complex mediates Ca2+-dependent cell-cell interactions that are essential for normal developmental processes. It has been proposed that sorting of cells during embryonic development is due, at least in part, to expression of different cadherin family members or to expression of differing levels of a single family member. Expression of dominant-negative cadherins has been used experimentally to decrease cell-cell interactions in whole organisms and in cultured cells. In this study, we elucidated the mechanism of action of extracellular domain-deleted dominant-negative cadherin, showing that it is not cadherin isotype-specific, and that it must be membrane-associated but the orientation within the membrane does not matter. In addition, membrane-targeted cytoplasmic domain cadherin with the catenin-binding domain deleted does not function as a dominant-negative cadherin. Expression of extracellular domain-deleted dominant-negative cadherin results in down-regulation of endogenous cadherins which presumably contributes to the non-adhesive phenotype.
Collapse
Affiliation(s)
- M T Nieman
- Department of Biology, University of Toledo, Toledo, OH 43606, USA
| | | | | | | |
Collapse
|
39
|
Hanes J, Jermutus L, Schaffitzel C, Plückthun A. Comparison of Escherichia coli and rabbit reticulocyte ribosome display systems. FEBS Lett 1999; 450:105-10. [PMID: 10350066 DOI: 10.1016/s0014-5793(99)00475-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ribosome display is a technology for library selection and simultaneous molecular evolution in vitro. We present here a comparison between an optimized Escherichia coli system and different rabbit reticulocyte ribosome display systems, optimized in a number of parameters, as a coupled eukaryotic system had been suggested to result in high enrichment factors [He and Taussig (1997) Nucleic Acids Res. 25, 5132-5134]. With all systems, antibody scFv fragments, complexed to the ribosomes and the corresponding mRNA, were enriched by binding to their cognate antigen and enrichment was always dependent on the absence of a stop codon and the presence of cognate antigen. However, the efficiency of the E. coli ribosome display system was 100-fold higher than an optimized uncoupled rabbit reticulocyte ribosome display system, with separate in vitro transcription and translation, which was in turn several-fold more efficient than the reported coupled system. Neither the E. coli nor the rabbit reticulocyte ribosome display system was dependent on the orientation of the domains of an antibody scFv fragment or on the spacer sequence. In summary, we could not detect any intrinsic advantage of using a eukaryotic translation system for ribosome display.
Collapse
Affiliation(s)
- J Hanes
- Biochemisches Institut der Universität Zürich, Switzerland
| | | | | | | |
Collapse
|
40
|
Lubon H. Transgenic animal bioreactors in biotechnology and production of blood proteins. BIOTECHNOLOGY ANNUAL REVIEW 1999; 4:1-54. [PMID: 9890137 DOI: 10.1016/s1387-2656(08)70066-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The regulatory elements of genes used to target the tissue-specific expression of heterologous human proteins have been studied in vitro and in transgenic mice. Hybrid genes exhibiting the desired performance have been introduced into large animals. Complex proteins like protein C, factor IX, factor VIII, fibrinogen and hemoglobin, in addition to simpler proteins like alpha 1-antitrypsin, antithrombin III, albumin and tissue plasminogen activator have been produced in transgenic livestock. The amount of functional protein secreted when the transgene is expressed at high levels may be limited by the required posttranslational modifications in host tissues. This can be overcome by engineering the transgenic bioreactor to express the appropriate modifying enzymes. Genetically engineered livestock are thus rapidly becoming a choice for the production of recombinant human blood proteins.
Collapse
Affiliation(s)
- H Lubon
- Plasma Derivatives Department, American Red Cross, Rockville, Maryland, USA.
| |
Collapse
|
41
|
Wang XL, Badenhop RB, Sim AS, Wilcken DE. The effect on transcription efficiency of the apolipoprotein AI gene of DNA variants at the 5' untranslated region. INTERNATIONAL JOURNAL OF CLINICAL & LABORATORY RESEARCH 1999; 28:235-41. [PMID: 9879497 DOI: 10.1007/s005990050051] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Elevated circulating levels of high-density lipoprotein and apolipoprotein AI are associated with reduced coronary artery disease risk. We have shown that a C to T substitution at +83 bp and a G to A substitution at -75 bp of the apolipoprotein AI gene are both related to increased high-density lipoprotein levels in a healthy population but not in a coronary population, among whom the same mutations are associated with increased disease severity. In the present study, we explored the effects of these base changes on transcriptional efficiency in vitro. We directionally cloned (using polymerase chain reaction) the 5' region of the apolipoprotein AI gene (-281 to +330 bp) with GC, GT, and AC haplotypes into a pGL3-luciferase reporter gene basic vector, and transfected the constructed vectors into HepG2 cells. The cells carrying the T allele at the +83 bp site (GT 112.3 +/- 12.4) had the same transcriptional efficiency as those bearing the C allele (GC 126.3 +/- 9.6). However, for cells with the A allele at -75 bp there was a twofold decrease in transcription (AC 63.1 +/- 9.3) accompanied by similar changes in Luc+ mRNA levels; this reduced transcription was only present if the apolipoprotein AI leader sequence was included in the insert. While the findings are inconsistent with the T or A allele being associated with higher high-density lipoprotein levels, they are consistent with the finding that the alleles are associated with an increased coronary artery disease risk, and demonstrate that the 5' leader region of the apolipoprotein AI gene participates in regulating apolipoprotein AI transcription. They also suggest that other regions of the apolipoprotein AI gene may have an active role in such regulation, and that environmental effects may influence allele-specific expression.
Collapse
Affiliation(s)
- X L Wang
- Department of Cardiovascular Medicine, University of New South Wales, Prince Henry/Prince of Wales Hospitals, Australia
| | | | | | | |
Collapse
|
42
|
Corti C, Restituito S, Rimland JM, Brabet I, Corsi M, Pin JP, Ferraguti F. Cloning and characterization of alternative mRNA forms for the rat metabotropic glutamate receptors mGluR7 and mGluR8. Eur J Neurosci 1998; 10:3629-41. [PMID: 9875342 DOI: 10.1046/j.1460-9568.1998.00371.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Novel mRNA isoforms for two members of the group III metabotropic glutamate receptors (mGluRs), called mGluR7b and mGluR8b, were identified from rat brain cerebral cortex and hippocampus. In both cases, the alternative splicing is generated by a similar out-of-frame insertion in the carboxyl-terminus that results in the replacement of the last 16 amino acids of mGluR7 and mGluR8 by 23 and 16 different amino acids, respectively. Distribution analysis for mGluR7 and mGluR8 isoforms revealed that the two splice variants are generally coexpressed in the same brain areas. The few exceptions were the olfactory bulb, in which only the mGluR7a form could be detected by reverse transcription-polymerase chain reaction, and the lateral reticular and ambiguous nuclei, which showed only mGluR8a labelling. Despite expression in the same regions, different mRNA abundance for the two variants of each receptor were observed. When transiently coexpressed in HEK 293 cells with the phospholipase C-activating chimeric G alpha qi9-G-protein, the a and b forms for both receptor subtypes showed a similar pharmacological profile. The rank order of potencies for both was: DL-amino-4-phosphonobutyrate > L-serine-O-phosphate > glutamate. However, the agonist potencies were significantly higher for mGluR8a, b compared with mGluR7a,b. In Xenopus oocytes, glutamate evoked currents only with mGluR8 when coexpressed with Kir 3.1 and 3.4. Glutamate-induced currents were antagonized by the group II/III antagonist (RS)-alpha-cyclopropyl-4-phosphonophenylglycine. In conclusion, the two isoforms of each receptor have identical pharmacological profiles when expressed in heterologous systems, despite structural differences in the carboxyl-terminal domains.
Collapse
Affiliation(s)
- C Corti
- Department of Pharmacology, GlaxoWellcome Medicines Research Centre, Verona, Italy
| | | | | | | | | | | | | |
Collapse
|
43
|
Cihlar T, Fuller MD, Cherrington JM. Expression of the catalytic subunit (UL54) and the accessory protein (UL44) of human cytomegalovirus DNA polymerase in a coupled in vitro transcription/translation system. Protein Expr Purif 1997; 11:209-18. [PMID: 9367818 DOI: 10.1006/prep.1997.0781] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The catalytic subunit (UL54) and accessory protein (UL44) of human cytomegalovirus (HCMV) DNA polymerase have been cloned and expressed in an in vitro-coupled transcription/translation reticulocyte lysate system. The influence of the 5'-untranslated region (5'-UTR) on the efficiency of expression from the circular plasmids has been investigated. For expression of both UL54 and UL44, a truncated form of the alfalfa mosaic virus (AMV) RNA4 5'-UTR was found to be superior to the full-length AMV 5'-UTR or the original HCMV 5'-UTRs of different lengths. Protein products with Mr approximately 140 and 55 kDa were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis in the UL54 and UL44 in vitro expression reactions, respectively. The properties of the expressed enzyme were compared with those of native HCMV DNA polymerase purified from HCMV-infected cells. DNA polymerase and 3'-5' exonuclease activities of the expressed UL54/UL44 complex were found to be dependent on salt concentration in the same manner as the activities of the native enzyme. The in vitro-expressed enzyme resembles the purified HCMV DNA polymerase in its affinity for deoxynucleoside triphosphates as well as in its sensitivity to known inhibitors (cidofovir diphosphate, ganciclovir triphosphate, and foscarnet). This straightforward method for protein expression may also be applicable to other enzymes where reproducible generation of fully functional products is desirable.
Collapse
Affiliation(s)
- T Cihlar
- Gilead Sciences, 333 Lakeside Drive, Foster City, California 94404, USA.
| | | | | |
Collapse
|
44
|
Hughes MJ, Andrews DW. A single nucleotide is a sufficient 5' untranslated region for translation in an eukaryotic in vitro system. FEBS Lett 1997; 414:19-22. [PMID: 9305724 DOI: 10.1016/s0014-5793(97)00965-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The 5' untranslated region of an RNA molecule is thought to play an important role in the regulation of translation. Following a recent report that a single nucleotide is sufficient to act in this role in the unicellular organism Giardia, we show that this is also the case for a mammalian in vitro system. These results also demonstrate that an RNA can initiate translation from a start codon where an ideal translational consensus sequence is impossible.
Collapse
Affiliation(s)
- M J Hughes
- Dept. of Biochemistry, McMaster University, Hamilton, ON, Canada
| | | |
Collapse
|
45
|
Hogenesch JB, Chan WK, Jackiw VH, Brown RC, Gu YZ, Pray-Grant M, Perdew GH, Bradfield CA. Characterization of a subset of the basic-helix-loop-helix-PAS superfamily that interacts with components of the dioxin signaling pathway. J Biol Chem 1997; 272:8581-93. [PMID: 9079689 DOI: 10.1074/jbc.272.13.8581] [Citation(s) in RCA: 360] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In an effort to better understand the mechanism of toxicity of 2,3,7, 8-tetrachlorodibenzo-p-dioxin, we employed an iterative search of human expressed sequence tags to identify novel basic-helix-loop-helix-PAS (bHLH-PAS) proteins that interact with either the Ah receptor (AHR) or the Ah receptor nuclear translocator (ARNT). We characterized five new "members of the PAS superfamily," or MOPs 1-5, that are similar in size and structural organization to the AHR and ARNT. MOPs 1-4 have N-terminal bHLH and PAS domains and C-terminal variable regions. MOP5 contained the characteristic PAS domain and a variable C terminus; it is possible that the cDNA contains a bHLH domain, but the entire open reading frame has yet to be completed. Coimmunoprecipitation studies, yeast two-hybrid analysis, and transient transfection experiments demonstrated that MOP1 and MOP2 dimerize with ARNT and that these complexes are transcriptionally active at defined DNA enhancer sequences in vivo. MOP3 was found to associate with the AHR in vitro but not in vivo. This observation, coupled with the fact that MOP3 formed tighter associations with the 90-kDa heat shock protein than the human AHR, suggests that MOP3 may be a conditionally active bHLH-PAS protein that requires activation by an unknown ligand. The expression profiles of the AHR, MOP1, and MOP2 mRNAs, coupled with the observation that they all share ARNT as a common dimeric partner, suggests that the cellular pathways mediated by MOP1 and MOP2 may influence or respond to the dioxin signaling pathway.
Collapse
Affiliation(s)
- J B Hogenesch
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Desjardins P, Pilon AA, Hassell JA, Mes-Masson AM. Polyomavirus large T-antigen binds the "pRb related' protein p130 through sequences in conserved region 2. Virus Res 1997; 47:85-90. [PMID: 9037740 DOI: 10.1016/s0168-1702(96)01404-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The transforming potential of DNA tumor viruses derives mainly from the ability of their encoded oncogene products to interact with cellular proteins. Many of these viral oncoproteins share regions of sequence similarity, designated conserved region 1 and 2, which have been implicated in complex formation with pRb, the product of the retinoblastoma tumor suppressor gene, and related p107 and p130 species. It has now been shown that the EIA protein of adenovirus is able to bind to all three pRb-related proteins through sequences in conserved region 1 and 2. We have shown previously that polyomavirus large T-antigen also interacts with pRb and p107 in vitro. The pRb and p107 binding domains reside between residues 141, 158 which include conserved region 2. In the present study, we demonstrate that polyomavirus large T-antigen also interacted with p130 in vitro through the same sequences in conserved region 2.
Collapse
Affiliation(s)
- P Desjardins
- Institute for Molecular Biology and Biotechnology, McMaster University, Hamilton, Ontario, Canada
| | | | | | | |
Collapse
|
47
|
Pinto M, Lobe CG. Products of the grg (Groucho-related gene) family can dimerize through the amino-terminal Q domain. J Biol Chem 1996; 271:33026-31. [PMID: 8955148 DOI: 10.1074/jbc.271.51.33026] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The murine grg (Groucho-related gene) products are believed to interact with transcription factors and repress transcription, thereby regulating cell proliferation and differentiation. Most proteins in the grg family contain all of the domains found in the Drosophila Groucho protein, including the S/P (Ser-Pro-rich) domain required for interaction with transcription factors and the WD40 domain, which is thought to interact with other proteins. However, at least two Grg proteins contain only the amino-terminal Q (glutamine-rich) domain. We examined whether the Q domain is used for dimerization between Grg proteins, using the yeast two-hybrid system and binding assays with glutathione S-transferase fusion proteins. We found that Grg proteins are able to dimerize through the Q domain and that dimerization requires a core of 50 amino acids. Surprisingly, the dimerization does not require the leucine zipper located within the Q domain.
Collapse
Affiliation(s)
- M Pinto
- Molecular Biology Institute, Cancer Research Group and Departments of Biochemistry and Medical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | | |
Collapse
|
48
|
Pilon AA, Mes-Masson AM. Polyomavirus large T antigen zinc finger is not required for efficient cellular immortalization of primary rat embryo fibroblasts. Virus Res 1996; 46:171-5. [PMID: 9029789 DOI: 10.1016/s0168-1702(96)01382-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The polyomavirus large T antigen contains a zinc finger domain required for the formation of hexamers involved in viral DNA replication. Since mutations within the zinc finger domains of transforming proteins like SV40 large T antigen and human papilloma virus E7 protein generally decrease their overall transforming activity, we have examined the ability of a mutant polyomavirus large T antigen that harbors a deletion in sequences within the zinc finger motif to immortalize primary rat embryo fibroblasts. In contrast to result obtained with SV40 large T antigen and the human papilloma virus E7 protein we show that deletion of the entire zinc finger motif enhances the immortalization efficiency of this mutant T antigen.
Collapse
Affiliation(s)
- A A Pilon
- Centre de recherche Louis-Charles Simard Institut du cancer de Montréal, Québec, Canada
| | | |
Collapse
|
49
|
Wahl JK, Sacco PA, McGranahan-Sadler TM, Sauppé LM, Wheelock MJ, Johnson KR. Plakoglobin domains that define its association with the desmosomal cadherins and the classical cadherins: identification of unique and shared domains. J Cell Sci 1996; 109 ( Pt 5):1143-54. [PMID: 8743961 DOI: 10.1242/jcs.109.5.1143] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two cell-cell junctions, the adherens junction and the desmosome, are prominent in epithelial cells. These junctions are composed of transmembrane cadherins which interact with cytoplasmic proteins that serve to link the cadherin to the cytoskeleton. One component of both adherens junctions and desmosomes is plakoglobin. In the adherens junction plakoglobin interacts with both the classical cadherin and with alpha-catenin. Alpha-catenin in turn interacts with microfilaments. The role plakoglobin plays in the desmosome is not well understood. Plakoglobin interacts with the desmosomal cadherins, but how and if this mediates interactions with the intermediate filament cytoskeleton is not known. Here we compare the domains of plakoglobin that allow it to associate with the desmosomal cadherins with those involved in interactions with the classical cadherins. We show that three sites on plakoglobin are involved in associations with the desmosomal cadherins. A domain near the N terminus is unique to the desmosomal cadherins and overlaps with the site that interacts with alpha-catenin, suggesting that there may be competition between alpha-catenin and the desmosomal cadherins for interactions with plakoglobin. In addition, a central domain is shared with regions used by plakoglobin to associate with the classical cadherins. Finally, a domain near the C terminus is shown to strongly modulate the interactions with the desmosomal cadherins. This latter domain also contributes to the association of plakoglobin with the classical cadherins.
Collapse
Affiliation(s)
- J K Wahl
- Department of Biology, University of Toledo, OH 43606, USA
| | | | | | | | | | | |
Collapse
|
50
|
Young JC, Andrews DW. The signal recognition particle receptor alpha subunit assembles co-translationally on the endoplasmic reticulum membrane during an mRNA-encoded translation pause in vitro. EMBO J 1996; 15:172-81. [PMID: 8598200 PMCID: PMC449929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Many proteins, including the alpha subunit of the signal recognition particle receptor (SR alpha), are targeted within the cell by poorly defined mechanisms. A 140 residue N-terminal domain of SR alpha targets and anchors the polypeptide to the endoplasmic reticulum membrane by a mechanism independent of the pathway involving the signal recognition particle. To investigate the mechanism of membrane anchoring, translation pause sites on the SR alpha mRNA were used to examine the targeting of translation intermediates. A strong pause site at nucleotide 507 of the mRNA open reading frame corresponded with the shortest nascent SR alpha polypeptide able to assemble on membranes. An mRNA sequence at this pause site that resembles a class of viral -1 frameshift sequences caused translation pausing when transferred into another mRNA context. Site-directed mutagenesis of the mRNA greatly reduced translation pausing without altering the polypeptide sequence, demonstrating unambiguously a role for this mRNA sequence in translation pausing. SR alpha polypeptides synthesized from the non-pausing mRNA were impaired in co-translational membrane anchoring. Furthermore, co-translational membrane assembly of SR alpha appears to anchor polysomes translating SR alpha to membranes.
Collapse
Affiliation(s)
- J C Young
- Department of Biochemistry, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada L8N 3Z5
| | | |
Collapse
|