Analysis of Context Sequence Surrounding Translation Initiation Site from Complete Genome of Model Plants
Authors: Rangan, L.1; Vogel, C.2; Srivastava, A.3
Source: Molecular Biotechnology, Volume 39, Number 3, July 2008 , pp. 207-213(7)
Publisher: Humana Press
Abstract:
Regions flanking the translation initiation site (TIS) are thought to play a crucial role in translation efficiency of mRNAs, but their exact sequence and evolution in eukaryotes are still a matter of debate. We investigated the context sequences in 20 nucleotides around the TIS in multi-cellular eukaryotes, with a focus on two model plants and a comparison to human. We identified consensus sequences aaaaaaa(A/G)(A/C)aAUGGcgaataata and ggcggc(g/c)(A/G)(A/C)(G/C)AUGGCggcggcgg for Arabidopsis thaliana and Oryza sativa, respectively. We observe strongly conserved G at position +4 and A or C at position −2; however, the exact nucleotide frequencies vary between the three organisms even at these conserved positions. The frequency of pyrimidines, which are considered sub optimum at position -3, is higher in both plants than in human. Arabidopsis is GC-depleted (AU-enriched) compared to both rice and human, and the enrichment is slightly stronger upstream than downstream of AUG. While both plants are similar though not identical in their variation of nucleotide frequencies, rice and human are more similar to each other than Arabidopsis and human. All three organisms display clear periodicity in A + G and C + U content when analyzing normalized frequencies. These findings suggest that, besides few highly conserved positions, overall structure of the context sequence plays a larger role in TIS recognition than the actual nucleotide frequencies.Keywords: A. thaliana; Consensus sequence; Eukaryotes; O. sativa; Translation initiation site
Document Type: Research article
DOI: 10.1007/s12033-008-9036-9
Affiliations: 1: Department of Biotechnology, Indian Institute of Technology Guwahati, North Guwahati, Assam, 781 039, India, Email: lrangan@iitg.ernet.in 2: Institute for Cellular and Molecular Biology, University of Texas at Austin, 2500 Speedway, Austin, TX, USA, 3: Department of Biotechnology, Indian Institute of Technology Guwahati, North Guwahati, Assam, 781 039, India,

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