- 関
- initiation codon、start codon
WordNet
- major food fish of Arctic and cold-temperate waters (同)codfish
- lean white flesh of important North Atlantic food fish; usually baked or poached (同)codfish
- a specific sequence of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for synthesizing a particular amino acid
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- =codfish 1
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出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2015/08/21 15:06:09」(JST)
[Wiki en表示]
The start codon is the first codon of a messenger RNA (mRNA) transcript translated by a ribosome. The start codon always codes for methionine in eukaryotes and a modified Met (fMet) in prokaryotes. The most common start codon is AUG.
The start codon is often preceded by a 5' untranslated region (5' UTR). In prokaryotes this includes the ribosome binding site.
Contents
- 1 Alternative start codons
- 1.1 Eukaryotes
- 1.2 Prokaryotes
- 2 Standard genetic code
- 3 See also
- 4 External links
- 5 References
Alternative start codons
Alternative start codons are different from the standard AUG codon and are found in both prokaryotes (bacteria) and eukaryotes. Alternate start codons are still translated as Met when they are at the start of a protein (even if the codon encodes a different amino acid otherwise). This is because a separate transfer RNA (tRNA) is used for initiation.[1]
Bioinformatics programs usually allow for alternate start codons when searching for protein coding genes.[citation needed]
Eukaryotes
Alternate start codons (non AUG) are very rare in eukaryotic genomes. However, naturally occurring non-AUG start codons have been reported for some cellular mRNAs.[2] Seven out of the nine possible single-nucleotide substitutions at the AUG start codon of dihydrofolate reductase were functional as translation start sites in mammalian cells.[3] In addition to the canonical Met-tRNA Met and AUG codon pathway, mammalian cells can initiate translation with leucine using a specific leucyl-tRNA that decodes the codon CUG.[4][5]
Mitochondrial genomes (and prokaryotes) use alternate start codons more significantly (AUA and AUU in humans and mainly GUG and UUG in prokaryotes).[citation needed]
Prokaryotes
E. coli uses 83% AUG (3542/4284), 14% (612) GUG, 3% (103) UUG [6] and one or two others (e.g., an AUU and possibly a CUG).[7][8]
Well-known coding regions that do not have AUG initiation codons are those of lacI (GUG)[9][10] and lacA (UUG)[11] in the E. coli lac operon.
Standard genetic code
nonpolar |
polar |
basic |
acidic |
(stop codon) |
Standard genetic code
1st
base |
2nd base |
3rd
base |
U |
C |
A |
G |
U |
UUU |
(Phe/F) Phenylalanine |
UCU |
(Ser/S) Serine |
UAU |
(Tyr/Y) Tyrosine |
UGU |
(Cys/C) Cysteine |
U |
UUC |
UCC |
UAC |
UGC |
C |
UUA |
(Leu/L) Leucine |
UCA |
UAA |
Stop (Ochre) |
UGA |
Stop (Opal) |
A |
UUG |
UCG |
UAG |
Stop (Amber) |
UGG |
(Trp/W) Tryptophan |
G |
C |
CUU |
CCU |
(Pro/P) Proline |
CAU |
(His/H) Histidine |
CGU |
(Arg/R) Arginine |
U |
CUC |
CCC |
CAC |
CGC |
C |
CUA |
CCA |
CAA |
(Gln/Q) Glutamine |
CGA |
A |
CUG |
CCG |
CAG |
CGG |
G |
A |
AUU |
(Ile/I) Isoleucine |
ACU |
(Thr/T) Threonine |
AAU |
(Asn/N) Asparagine |
AGU |
(Ser/S) Serine |
U |
AUC |
ACC |
AAC |
AGC |
C |
AUA |
ACA |
AAA |
(Lys/K) Lysine |
AGA |
(Arg/R) Arginine |
A |
AUG[A] |
(Met/M) Methionine |
ACG |
AAG |
AGG |
G |
G |
GUU |
(Val/V) Valine |
GCU |
(Ala/A) Alanine |
GAU |
(Asp/D) Aspartic acid |
GGU |
(Gly/G) Glycine |
U |
GUC |
GCC |
GAC |
GGC |
C |
GUA |
GCA |
GAA |
(Glu/E) Glutamic acid |
GGA |
A |
GUG |
GCG |
GAG |
GGG |
G |
- A The codon AUG both codes for methionine and serves as an initiation site: the first AUG in an mRNA's coding region is where translation into protein begins.[12]
See also
- Central dogma of molecular biology
- Codon
- Messenger RNA
- Stop codon
- Transfer RNA
- Translation
External links
- The Genetic Codes. Compiled by Andrzej (Anjay) Elzanowski and Jim Ostell, National Center for Biotechnology Information (NCBI), Bethesda, Maryland, U.S.A.[1]
References
- ^ Lobanov, A. V.; Turanov, A. A.; Hatfield, D. L.; Gladyshev, V. N. (2010). "Dual functions of codons in the genetic code". Critical Reviews in Biochemistry and Molecular Biology 45 (4): 257–65. doi:10.3109/10409231003786094. PMC 3311535. PMID 20446809. edit
- ^ Ivanov IP, Firth AE, Michel AM, Atkins JF, Baranov PV (2011). "Identification of evolutionarily conserved non-AUG-initiated N-terminal extensions in human coding sequences". Nucleic Acids Research 39 (10): 4220–4234. doi:10.1093/nar/gkr007. PMC 3105428. PMID 21266472. edit
- ^ Peabody, D. S. (1989). "Translation initiation at non-AUG triplets in mammalian cells". The Journal of Biological Chemistry 264 (9): 5031–5. PMID 2538469. edit
- ^ Starck, S. R.; Jiang, V; Pavon-Eternod, M; Prasad, S; McCarthy, B; Pan, T; Shastri, N (2012). "Leucine-tRNA initiates at CUG start codons for protein synthesis and presentation by MHC class I". Science 336 (6089): 1719–23. doi:10.1126/science.1220270. PMID 22745432. edit
- ^ Dever, T. E. (2012). "Molecular biology. A new start for protein synthesis". Science 336 (6089): 1645–6. doi:10.1126/science.1224439. PMID 22745408. edit
- ^ Blattner, F. R.; Plunkett g, G.; Bloch, C. A.; Perna, N. T.; Burland, V.; Riley, M.; Collado-Vides, J.; Glasner, J. D.; Rode, C. K.; Mayhew, G. F.; Gregor, J.; Davis, N. W.; Kirkpatrick, H. A.; Goeden, M. A.; Rose, D. J.; Mau, B.; Shao, Y. (1997). "The Complete Genome Sequence of Escherichia coli K-12". Science 277 (5331): 1453–1462. doi:10.1126/science.277.5331.1453. PMID 9278503. edit
- ^ Sacerdot, C.; Fayat, G.; Dessen, P.; Springer, M.; Plumbridge, J. A.; Grunberg-Manago, M.; Blanquet, S. (1982). "Sequence of a 1.26-kb DNA fragment containing the structural gene for E.coli initiation factor IF3: Presence of an AUU initiator codon". The EMBO journal 1 (3): 311–315. PMC 553041. PMID 6325158. edit
- ^ Missiakas, D.; Georgopoulos, C.; Raina, S. (1993). "The Escherichia coli heat shock gene htpY: Mutational analysis, cloning, sequencing, and transcriptional regulation". Journal of bacteriology 175 (9): 2613–2624. PMC 204563. PMID 8478327. edit
- ^ E.coli lactose operon with lacI, lacZ, lacY and lacA genes GenBank: J01636.1
- ^ Farabaugh, P. J. (1978). "Sequence of the lacI gene". Nature 274 (5673): 765–769. doi:10.1038/274765a0. PMID 355891. edit
- ^ NCBI Sequence Viewer v2.0
- ^ Nakamoto T (March 2009). "Evolution and the universality of the mechanism of initiation of protein synthesis". Gene 432 (1–2): 1–6. doi:10.1016/j.gene.2008.11.001. PMID 19056476.
UpToDate Contents
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English Journal
- Diamond Blackfan anemia: a Cheshire cat of hematology.
- Farrar JE.
- Pediatric blood & cancer.Pediatr Blood Cancer.2014 Jul;61(7):1154-5. doi: 10.1002/pbc.25014. Epub 2014 Mar 14.
- PMID 24634369
- Loss of GATA-1 full length as a cause of Diamond-Blackfan anemia phenotype.
- Parrella S1, Aspesi A, Quarello P, Garelli E, Pavesi E, Carando A, Nardi M, Ellis SR, Ramenghi U, Dianzani I.
- Pediatric blood & cancer.Pediatr Blood Cancer.2014 Jul;61(7):1319-21. doi: 10.1002/pbc.24944. Epub 2014 Jan 22.
- Mutations in the hematopoietic transcription factor GATA-1 alter the proliferation/differentiation of hemopoietic progenitors. Mutations in exon 2 interfere with the synthesis of the full-length isoform of GATA-1 and lead to the production of a shortened isoform, GATA-1s. These mutations have been f
- PMID 24453067
- Taura syndrome virus IRES initiates translation by binding its tRNA-mRNA-like structural element in the ribosomal decoding center.
- Koh CS1, Brilot AF2, Grigorieff N3, Korostelev AA4.
- Proceedings of the National Academy of Sciences of the United States of America.Proc Natl Acad Sci U S A.2014 Jun 24;111(25):9139-44. doi: 10.1073/pnas.1406335111. Epub 2014 Jun 9.
- In cap-dependent translation initiation, the open reading frame (ORF) of mRNA is established by the placement of the AUG start codon and initiator tRNA in the ribosomal peptidyl (P) site. Internal ribosome entry sites (IRESs) promote translation of mRNAs in a cap-independent manner. We report two st
- PMID 24927574
Japanese Journal
- Gene expression and function involved in polyol biosynthesis of Trichosporonoides megachiliensis under hyper-osmotic stress(MICROBIAL PHYSIOLOGY AND BIOTECHNOLOGY)
- Kobayashi Yosuke,Yoshida Junjiro,Iwata Hisashi,Koyama Yoshiyuki,Kato Jun,Ogihara Jun,Kasumi Takafumi
- Journal of bioscience and bioengineering 115(6), 645-650, 2013-06
- … Among three erythritol reductase isogenes (er1, er2, and er3) in Trichosporonoides megachiliensis SN-124A, er1 and er2 each had one stress response element (STRE) approximately 2 kbp upstream of their respective initiator codon; … in contrast, er3 had two STREs, 148 and 40 bp upstream from the initiator codon. …
- NAID 110009614948
- Four-Base Codon-Mediated Saturation Mutagenesis in a Cell-Free Translation System(ENZYMOLOGY, PROTEIN ENGINEERING, AND ENZYME TECHNOLOGY)
- Watanabe Takayoshi,Muranaka Norihito,Hohsaka Takahiro
- Journal of bioscience and bioengineering 105(3), 211-215, 2008-03-25
- … We have developed a simple and rapid method for the expression of mutated proteins with comprehensive single amino acid substitutions from single mutated genes having a four-base codon in a cell-free translation system. … In the presence of one of the amino-acyl-tRNAs, a streptavidin mRNA with a four-base codon at the Tyr83 position was expressed in an Escherichia coli cell-free translation system. …
- NAID 110006632551
- Characterization of the Promoter of the Mouse Preproorexin Gene
- Kato Haruno,Hosoda Hiroshi,Fukuda Toru [他],MASUSHIGE Shoichi,KIDA Satoshi
- Bioscience, biotechnology, and biochemistry 71(3), 840-843, 2007-03-23
- … We determined that the transcription start site (+1) is located 96 nucleotides upstream of the initiation codon. … The start site region contained consensus sequences corresponding to the transcription initiator and TATA box. …
- NAID 10027513166
Related Links
- A codon that acts as a start signal for the synthesis of a polypeptide. ... mRNA, or messenger-RNA, contains the codons used in the process of translating RNA into proteins. The tRNA, or transfer-RNA molecules, contain the anti ...
- Definition of INITIATOR CODON: The sequence AUG or rarely GUG which always specifies the first amino acid of a protein. See panel on DNA and the genetic code ... Link to This Definition Did you find this definition of INITIATOR ...
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