Vertebrate mitochondrial code

The vertebrate mitochondrial code is the genetic code found in the mitochondria of all vertebrata.

Evolution

AGA and AGG were thought to have become mitochondrial stop codons early in vertebrate evolution.[1] However, at least in humans it has now been shown that AGA and AGG sequences are not recognized as termination codons. A -1 mitoribosome frameshift occurs at the AGA and AGG codons predicted to terminate the CO1 and ND6 open reading frames (ORFs), and consequently both ORFs terminate in the standard UAG codon.[2]

Incomplete stop codons

Mitochondrial genes in some vertebrates (including humans) have incomplete stop codons ending in U or UA, which become complete termination codons (UAA) upon subsequent polyadenylation.[3][4][5][6]

Translation table

AAs    = FFLLSSSSYY**CCWWLLLLPPPPHHQQRRRRIIMMTTTTNNKKSS**VVVVAAAADDEEGGGG
Starts = --------------------------------MMMM---------------M------------
Base1  = TTTTTTTTTTTTTTTTCCCCCCCCCCCCCCCCAAAAAAAAAAAAAAAAGGGGGGGGGGGGGGGG
Base2  = TTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGG
Base3  = TCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAG

Bases: adenine (A), cytosine (C), guanine (G) and thymine (T) or uracil (U).

Amino acids: Alanine (Ala, A), Arginine (Arg, R), Asparagine (Asn, N), Aspartic acid (Asp, D), Cysteine (Cys, C), Glutamic acid (Glu, E), Glutamine (Gln, Q), Glycine (Gly, G), Histidine (His, H), Isoleucine (Ile, I), Leucine (Leu, L), Lysine (Lys, K), Methionine (Met, M), Phenylalanine (Phe, F), Proline (Pro, P), Serine (Ser, S), Threonine (Thr, T), Tryptophan (Trp, W), Tyrosine (Tyr, Y), Valine (Val, V)

Differences from the standard code:
This code Standard
AGATer * Arg R
AGGTer * Arg R
AUAMet M Ile I
UGATrp W Ter *

Alternative initiation codons

See also

References

  1. S. Osawa, T. Ohama, T. H. Jukes and K. Watanabe (September 1989). "Evolution of the mitochondrial genetic code. I. Origin of AGR serine and stop codons in metazoan mitochondria.". J Mol Evol. 29 (3): 202–7. doi:10.1007/bf02100203. PMID 2506356.
  2. R J Temperley; R Richter; S Dennerlein; R N Lightowlers; Z M Chrzanowska-Lightowlers (January 2010). "Hungry codons promote frameshifting in human mitochondrial ribosomes.". Science. 15 (327(5963)): 301. doi:10.1126/science.1180674. PMID 20075246.
  3. Temperley, R. J.; Wydro, M; Lightowlers, R. N.; Chrzanowska-Lightowlers, Z. M. (2010). "Human mitochondrial mRNAs--like members of all families, similar but different". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1797 (6–7): 1081–5. doi:10.1016/j.bbabio.2010.02.036. PMC 3003153Freely accessible. PMID 20211597.
  4. W. R. Hou, Y. Chen, X. Wu, J. C. Hu, Z. S. Peng, J. Yang, Z. X. Tang, C. Q. Zhou, Y. M. Li, S. K. Yang, Y. J. Du, L. L. Kong, Z. L. Ren, H. Y. Zhang and S. S. Shuai (December 2006). "A complete mitochondrial genome sequence of Asian black bear Sichuan subspecies (Ursus thibetanus mupinensis).". Int J Biol Sci. 23;3(2) (2): 85–90. doi:10.7150/ijbs.3.85. PMID 17205108.
  5. Oh, D. J.; Kim, J. Y.; Lee, J. A.; Yoon, W. J.; Park, S. Y.; Jung, Y. H. (2007). "Complete mitochondrial genome of the rabbitfish Siganus fuscescens (Perciformes, Siganidae)". DNA Sequence. 18 (4): 295–301. doi:10.1080/10425170701248525. PMID 17541835.
  6. Ki, J. S.; Hwang, D. S.; Park, T. J.; Han, S. H.; Lee, J. S. (2009). "A comparative analysis of the complete mitochondrial genome of the Eurasian otter Lutra lutra (Carnivora; Mustelidae)". Molecular Biology Reports. 37 (4): 1943. doi:10.1007/s11033-009-9641-0. PMID 19757186.
  7. P. Desjardins & R. Morais (February 1991). "Nucleotide sequence and evolution of coding and noncoding regions of a quail mitochondrial genome.". J Mol Evol. 32 (2): 153–161. doi:10.1007/bf02515387. PMID 1706782.
  8. The Genetic Codes

External links

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