WordNet

serve in a specific professional capacity; "the priest sat for confession"; "she sat on the jury"
be around, often idly or without specific purpose; "The object sat in the corner"; "We sat around chatting for another hour" (同)sit around
be seated (同)sit_down
be in session; "When does the court of law sit?"
be located or situated somewhere; "The White House sits on Pennsylvania Avenue"
a written record of a commercial transaction (同)accounting entry, ledger entry
an item inserted in a written record
work as an intern; "The young doctor is interning at the Medical Center this year"
an advanced student or graduate in medicine gaining supervised practical experience (`houseman is a British term) (同)interne, houseman, medical intern
deprive of freedom; "During WW II, Japanese were interned in camps in the West"
the piece of land on which something is located (or is to be located); "a good site for the school" (同)land site
physical position in relation to the surroundings; "the sites are determined by highly specific sequences of nucleotides" (同)situation
happening or arising or located within some limits or especially surface; "internal organs"; "internal mechanism of a toy"; "internal party maneuvering"
occurring within an institution or community; "intragroup squabbling within the corporation" (同)intragroup

PrepTutorEJDIC

(…に)『座る』,座っている《+『at』(『on, in』)+『名』》・着席する《+『down』》・(…に)〈鳥などが〉『止まる』,休む《+『on』+『名』》・〈めんどりが〉卵を抱く,巣に就く / 《場所の副詞[句]を伴って》(ある場所に)『位置する』・ (画家・写真家のために)ポーズをとる・しっとしている,動かないでいる・(議員・委員などの)職に就いている《+『on』+『名』》・〈議会・法廷などが〉開会(開廷)される・(…に)負担となる,重荷となる《+『on』(『upon』)+『名』》・〈衣服などが〉(…に)合う,似合う《+『on』+『名』》・〈人〉‘を'座らせる,着席させる《+『down』+『名,』+『名』+『down』》・〈馬〉‘に'乗る・《英》〈試験〉‘を'受ける
〈C〉〈U〉(場所などに)『入ること』,『入場』,登場;(団体・競技などへの)参加,加入(entrance)《+『into』+『名』》 / 〈C〉《おもに米》(‥への)入り口(entrance),玄関《+『of』(『to』)+『名』》 / 〈C〉(帳簿・日記・表などの)『記載事項』,項目;(…の)『記入』《+『of』+『名』》 / 〈C〉(競技・コンテストなどの)『参加者』,参加作品《+『for』(『in』)+『名』》 / 〈C〉(辞書などの)見出し語
(特に戦時中)〈人・船など〉‘を'強制収容する,抑留する
(町・建物などの)『場所』;敷地,用地 / 遺跡;(事件などの)現場 / 〈建物など〉‘を'位置させる(locate)
『内側の』,内部にある / 『国内の』(domestic) / 内からとる,内用の

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/07/17 18:40:33」(JST)

wiki en

An internal ribosome entry site, abbreviated IRES, is a nucleotide sequence that allows for translation initiation in the middle of a messenger RNA (mRNA) sequence as part of the greater process of protein synthesis. Usually, in eukaryotes, translation can be initiated only at the 5' end of the mRNA molecule, since 5' cap recognition is required for the assembly of the initiation complex.

History[edit]

These sequences were first discovered in 1988 in poliovirus RNA and encephalomyocarditis virus RNA in the labs of Nahum Sonenberg^[1] and Eckard Wimmer,^[2] respectively. They are described as distinct regions of RNA molecules that are able to attract the eukaryotic ribosome to the mRNA molecule and, therefore, allow translation initiation to occur. This process became known as the internal initiation of translation. It has been hypothesized that IRES elements have a distinct secondary or even tertiary structure, but similar structural features at the levels of either primary or secondary structure that are common to all IRES segments have not been reported to date.

Cancer: 5′-UTR of Laminin-B1 harbors IRES between −293 and −1 upstream of the start codon. [Petz 2011 [1]

Location[edit]

Poliovirus genome, including an IRES.

It is common that IRESes are located in the 5'UTR of RNA viruses and allow translation of the RNAs in a cap-independent manner. However, mRNAs of viruses from Dicistroviridae family possess two ORFs (open reading frames), translation of both being directed by two distinct IRESes. It was later suggested that some mammalian mRNAs also have IRES. Several cellular IRES elements are thought to be located in eukaryotic mRNAs encoding genes involved in stress survival, and other processes critical to survival. As of September 2009, there are 60 animal and 8 plant viruses reported to contain IRES segments and 115 mRNA sequences containing them as well.^[3]

Activation[edit]

IRES are often used by viruses as a means to ensure that viral translation is active during periods of time when host translation is inhibited. These mechanisms of host translation inhibition are varied, and can be initiated by both virus and host, depending on the type of virus in question. However, in the case of most picornaviruses, this is accomplished by the viral protease cleaving eIF-4G so that it cannot interact with eIF-4E. Interaction between these two initiation factors is necessary for mRNA 5'cap to 3'poly-A-tail loop formation, which is usually a necessary event for initiation of translation. The virus may even use the eIF-4G to aid in initiation of IRES-mediated translation.

The cell may also use IRES to increase translation of certain proteins during mitosis and programmed cell death. In mitosis, the cell dephosphorylates eIF-4E so that it has little affinity for the 5'cap. As a result, the pre-initiation mRNA loop is not formed, and the translational machinery is diverted to IRES within the mRNA. Many proteins involved in mitosis are encoded by IRES mRNA. In programmed cell death, cleavage of eIF-4G, such as performed by viruses, decreases translation. Lack of essential proteins contributes to the death of the cell, as does translation of IRES mRNA sequences coding proteins involved in controlling cell death.^[4]

Mechanism[edit]

The mechanism of viral IRES function to date is better characterized than the mechanism of cellular IRES function,^[5] for which no clear mechanism have been proposed yet. Hepatitis C Virus-related IRESs directly bind 40S ribosomal subunit in such a way that their initiator codons are located in ribosomal P-site without mRNA scanning. These IRESs do not require Eukaryotic initiation factors eIF1, 1A, 4A, 4B, and 4E. Picornavirus IRES do not attract 40S directly, but rather through high-affinity eIF4G-binding site.^[6] In addition, many viral IRES (as well as cellular IRES) require additional proteins to mediate their function, known as IRES trans-acting factors (ITAFs). The role of ITAFs in IRES function is currently the subject of intense research.

Testing[edit]

Testing a particular RNA sequence for IRES activity relies on a bicistronic reporter construct. When an IRES segment is located between two reporter open reading frames in a eukaryotic mRNA molecule (a bicistronic mRNA), it can drive translation of the downstream protein coding region independently of the 5'-cap structure bound to the 5' end of the mRNA molecule. In such a setup both proteins are produced in the cell. The first reporter protein located in the first cistron is synthesized by the cap-dependent initiation approach while translation initiation of the second protein is directed by the IRES segment located in the intercistronic spacer region between the two reporter protein coding regions. However, there are several caveats to be aware of when interpreting data produced using bicistronic reporter constructs.^[7] For example, there are several known cases of mis-reported IRES segments that were later recognized as promoter-containing regions. More recently, splice acceptor sites within several presumed IRES segments have been shown to be responsible for apparent IRES function in bicistronic reporter assays.^[8]

Types[edit]

Internal ribosome entry sites in viral genomes^[6]
Virus	IRES
Poliovirus	Picornavirus IRES
Rhinovirus	Picornavirus IRES
Encephalomyocarditis virus	Picornavirus IRES
Foot-and-mouth disease virus	Aphthovirus IRES
Hepatitis A virus	Hepatitis A IRES
Hepatitis C virus	Hepatitis C IRES
Classical swine fever virus	Pestivirus IRES
Bovine viral diarrhea virus	Pestivirus IRES
Friend murine leukemia
Moloney murine leukemia (MMLV)
Rous sarcoma virus
Human immunodeficiency virus
Plautia stali intestine virus	Cripavirus internal ribosome entry site (IRES)
Rhopalosiphum padi virus	Cripavirus internal ribosome entry site (IRES)
Cricket paralysis virus	Cripavirus internal ribosome entry site (IRES)
Triatoma virus	Cripavirus internal ribosome entry site (IRES)
Kaposi's sarcoma-associated herpesvirus	Kaposi's sarcoma-associated herpesvirus IRES
Marek's disease virus MDV	5'Leader IRES and intercistronic IRES in the 1.8-kb family of immediate early transcripts (IRES)1

Internal ribosome entry sites in cellular mRNAs^[6]
Protein type	Proteins
Growth factors	Fibroblast growth factor (FGF-1 IRES and FGF-2 IRES), Platelet-derived growth factor B (PDGF/c-sis IRES), Vascular endothelial growth factor (VEGF IRES), Insulin-like growth factor 2 (IGF-II IRES)
Transcription factors	Antennapedia, Ultrabithorax, MYT-2, NF-κB repressing factor NRF, AML1/RUNX1, Gtx homeodomain protein
Translation factors	Eukaryotic initiation factor 4G (elF4G)a, Eukaryotic initiation factor 4Gl (elF4Gl)a, Death associated protein 5 (DAP5)
Oncogenes	c-myc, L-myc, Pim-1, Protein kinase p58PITSLRE, p53
Transporters/receptors	Cationic amino acid transporter Cat-1, Nuclear form of Notch 2, Voltage-gated potassium channel
Activators of apoptosis	Apoptotic protease activating factor (Apaf-1)
Inhibitors of apoptosis	X-linked inhibitor of apoptosis (XIAP), HIAP2, Bcl-xL, Bcl-2
Proteins localized in neuronal dendrites	Activity-regulated cytoskeletal protein (ARC), α-subunit of calcium calmodulin dependent kinase II dendrin, Microtubule-associated protein 2 (MAP2), neurogranin (RC3), Amyloid precursor protein
Others	Immunoglobulin heavy chain binding protein (BiP), Heat shock protein 70, β-subunit of mitochondrial H+-ATP synthase, Ornithine decarboxylase, connexins 32 and 43, HIF-1α, APC

References[edit]

^ Pelletier J, Sonenberg N (1988). "Internal initiation of translation of eukaryotic mRNA directed by a sequence derived from poliovirus RNA". Nature 334 (6180): 320–5. doi:10.1038/334320a0. PMID 2839775.
^ Jang SK, Kräusslich HG, Nicklin MJ, Duke GM, Palmenberg AC, Wimmer E (August 1988). "A segment of the 5' nontranslated region of encephalomyocarditis virus RNA directs internal entry of ribosomes during in vitro translation". J. Virol. 62 (8): 2636–43. PMC 253694. PMID 2839690.
^ Mokrejs M, Vopálenský V, Kolenaty O, et al (January 2006). "IRESite: the database of experimentally verified IRES structures (www.iresite.org)". Nucleic Acids Res. 34 (Database issue): D125–30. doi:10.1093/nar/gkj081. PMC 1347444. PMID 16381829.
^ Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P. (2002). Molecular Biology of the Cell. Garland Science. pp. 447–448. ISBN 0-8153-4072-9.
^ López-Lastra M, Rivas A, Barría MI (2005). "Protein synthesis in eukaryotes: the growing biological relevance of cap-independent translation initiation". Biol. Res. 38 (2–3): 121–46. PMID 16238092.
^ ^a ^b ^c Hellen CU, Sarnow P (2001). "Internal ribosome entry sites in eukaryotic mRNA molecules". Genes Dev. 15 (13): 1593–612. doi:10.1101/gad.891101. PMID 11445534.
^ Kozak M (2005). "A second look at cellular mRNA sequences said to function as internal ribosome entry sites". Nucleic Acids Res. 33 (20): 6593–602. doi:10.1093/nar/gki958. PMC 1298923. PMID 16314320.
^ Baranick BT, Lemp NA, Nagashima J, Hiraoka K, Kasahara N, Logg CR (March 2008). "Splicing mediates the activity of four putative cellular internal ribosome entry sites". Proc. Nat. Acad. Sci. 105 (12): 4733–38. doi:10.1073/pnas.0710650105. PMC 2290820. PMID 18326627.

External links[edit]

IRESite
Malys N, McCarthy JEG (2010). "Translation initiation: variations in the mechanism can be anticipated". Cellular and Molecular Life Sciences 68 (6): 991–1003. doi:10.1007/s00018-010-0588-z. PMID 21076851. Unknown parameter |unused_data= ignored (help)

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English Journal

Expression of Recombinant Human Interferon-γ with Antiviral Activity in the Bi-Cistronic Baculovirus-Insect/Larval System.

Chen WS, Villaflores OB, Jinn TR, Chan MT, Chang YC, Wu TY.SourceInstitute of Molecular Medicine, National Tsing Hua University.
Bioscience, biotechnology, and biochemistry.Biosci Biotechnol Biochem.2011 Jul 7. [Epub ahead of print]
A bi-cistronic baculovirus-insect/larval system containing a polyhedron promoter, an internal ribosome entry site (IRES), and an egfp gene was developed as a cost-effective platform for the production of recombinant human interferon gamma (rhIFN-γ). There was no significant difference between the a
PMID 21737931

Expression of truncated eIF3e resulting from integration of MMTV causes a shift from Cap-dependent to Cap-independent translation.

Chiluiza D, Bargo S, Callahan R, Rhoads RE.SourceHarvard Medical School, United States;
The Journal of biological chemistry.J Biol Chem.2011 Jul 7. [Epub ahead of print]
Integration of mouse mammary tumor virus (MMTV) at the common integration site Int6 occurs in the gene encoding eIF3e, the p48 subunit of translation initiation factor eIF3. Integration is at any of several introns of the eIF3e gene and causes the expression of truncated eIF3e mRNAs. Ectopic express
PMID 21737453

Japanese Journal

Expression and Immunological Studies of Classical Swine Fever Virus Glycoprotein E2 in the Bi-Cistronic Baculovirus/Larvae Expression System

WU Chi-Ming,HSUAN Shih-Ling,CHEN Zeng-Weng,JINN Tzyy-Rong,HUANG Chienjin,LIAO Jiunn-Wang,CHEN Ter-Hsin,LIAO Chih-Ming,LEE Wei-Cheng,WU Tzong-Yuan,CHIEN Maw-Sheng
Bioscience, Biotechnology, and Biochemistry 74(7), 1343-1349, 2010
… To develop an economical, easy technique for producing recombinant E2 glycoprotein (rE2) of classical swine fever virus (CSFV) as a candidate immunogen, a bi-cistronic baculovirus/larvae expression vector was constructed using p10 promoter, an internal ribosome entry site, and the gfp gene. …
NAID 130000298193

Generation of Adeno-Associated Virus Vector Enabling Functional Expression of Oxytocin Receptor and Fluorescence Marker Genes Using the Human eIF4G Internal Ribosome Entry Site Element

SATO Keisuke,DATE Shiori,AOYAGI Yumi,KASAHARA Yoshiyuki,NAWA Akihiko,MIZUKAMI Hiroaki,HIDEMA Shizu,OZAWA Keiya,NISHIMORI Katsuhiko
Bioscience, Biotechnology, and Biochemistry 73(9), 2145-2148, 2009
We developed the AAV-Oxtr-IRES-Venus vector to rescue the oxytocin receptor (Oxtr) gene functionally at restricted regions in the brains of Oxtr knockout mice. First we chose human eIF4G gene-derived …
NAID 130000119652

Related Pictures

★リンクテーブル★

リンク元	「配列内リボソーム進入部位」「IRES」
関連記事	「entry」「sit」「internal」「site」「intern」

「配列内リボソーム進入部位」

　　[★]

英: internal ribosome entry site, internal ribosomal entry site, IRES

[show details]

配列内リボソーム進入部位 : 40 件
内部リボソーム進入シグナル : 5 件

真核生物mRNAの機能的ヌクレオチド配列の一種

「IRES」

　　[★] 配列内リボソーム進入部位 internal ribosome entry site

「entry」

　　[★]

n.

移行、侵入、流入、エントリー、入口

関: entrance、immigration、incurrent、inflow、influx、inlet、intrude、intrusion、invade、invasion、invasive、penetrate、penetration、shift、transfer、transit、transition、transitional、translocation、travel

「sit」

　　[★]

vi.

(過去-過去分詞sat)座る、位置する

関: lie、locate、location、loci、locus、map、position、rank、seat、situated、situation、stand、topo

「internal」

　　[★]

adj.

内部の、内の、体内の、内的な

関: endo、in vivo、interior、internally、intra

「site」

　　[★]

n.

部位、場所、サイト

関: location、loci、locus、place、topo

「intern」

　　[★]

n.

インターン、医学研修生

[Pelletier-1] Pelletier J, Sonenberg N (1988). "Internal initiation of translation of eukaryotic mRNA directed by a sequence derived from poliovirus RNA". Nature 334 (6180): 320–5. doi:10.1038/334320a0. PMID 2839775.

[Jang-2] Jang SK, Kräusslich HG, Nicklin MJ, Duke GM, Palmenberg AC, Wimmer E (August 1988). "A segment of the 5' nontranslated region of encephalomyocarditis virus RNA directs internal entry of ribosomes during in vitro translation". J. Virol. 62 (8): 2636–43. PMC 253694. PMID 2839690.

[pmid16381829-3] Mokrejs M, Vopálenský V, Kolenaty O, et al (January 2006). "IRESite: the database of experimentally verified IRES structures (www.iresite.org)". Nucleic Acids Res. 34 (Database issue): D125–30. doi:10.1093/nar/gkj081. PMC 1347444. PMID 16381829.

[4] Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P. (2002). Molecular Biology of the Cell. Garland Science. pp. 447–448. ISBN 0-8153-4072-9.

[5] López-Lastra M, Rivas A, Barría MI (2005). "Protein synthesis in eukaryotes: the growing biological relevance of cap-independent translation initiation". Biol. Res. 38 (2–3): 121–46. PMID 16238092.

[Hellen-6] Hellen CU, Sarnow P (2001). "Internal ribosome entry sites in eukaryotic mRNA molecules". Genes Dev. 15 (13): 1593–612. doi:10.1101/gad.891101. PMID 11445534.

[Kozak-7] Kozak M (2005). "A second look at cellular mRNA sequences said to function as internal ribosome entry sites". Nucleic Acids Res. 33 (20): 6593–602. doi:10.1093/nar/gki958. PMC 1298923. PMID 16314320.

[8] Baranick BT, Lemp NA, Nagashima J, Hiraoka K, Kasahara N, Logg CR (March 2008). "Splicing mediates the activity of four putative cellular internal ribosome entry sites". Proc. Nat. Acad. Sci. 105 (12): 4733–38. doi:10.1073/pnas.0710650105. PMC 2290820. PMID 18326627.

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案内

internal ribosome entry site