Details

Autor(en) / Beteiligte

• Reboll, Marc René
• Oumard, André
• Gazdag, Aniko Carla
• Renger, Isabelle
• Ritter, Birgit
• Schwarzer, Michael
• Hauser, Hansjoerg
• Wood, Monika
• Yamada, Michiyuki
• Resch, Klaus
• Nourbakhsh, Mahtab

Titel

NRF IRES activity is mediated by RNA binding protein JKTBP1 and a 14-nt RNA element

Ist Teil von

• RNA (Cambridge), 2007-08, Vol.13 (8), p.1328-1340

Ort / Verlag

United States: Cold Spring Harbor Laboratory Press

Erscheinungsjahr

2007

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• The mRNA of human NF-kappaB repressing factor (NRF) contains a long 5'-untranslated region (UTR) that directs ribosomes to the downstream start codon by a cap-independent mechanism. Comparison of the nucleotide (nt) sequences of human and mouse NRF mRNAs reveals a high degree of identity throughout a fragment of 150 nt proximal to the start codon. Here, we show that this region constitutes a minimal internal ribosome entry segment (IRES) module. Enzymatic RNA structure analysis reveals a secondary structure model of the NRF IRES module. Point mutation analysis of the module determines a short, 14-nt RNA element (nt 640-653) as a mediator of IRES function. Purification of IRES binding cellular proteins and subsequent ESI/MS/MS sequence analysis led to identification of the RNA-binding protein, JKTBP1. EMSA experiments show that JKTBP1 binds upstream to the 14-nt RNA element in the NRF IRES module (nt 579-639). Over-expression of JKTBP1 significantly enhances activity of the NRF IRES module in dicistronic constructs. Moreover, siRNA experiments demonstrate that down-regulation of endogenous JKTBP1 decreases NRF IRES activity and the level of endogenous NRF protein. The data of this study show that JKTBP1 and the 14-nt element act independently to mediate NRF IRES activity.