RegRNA
A Regulatory RNA Motifs and Elements Finder
  Release 1.0, Jan 2006
 
 
 

Accession R0015
Feature Type RegRNA in 5'-UTR
Name Internal Ribosome Entry Site (IRES)
Regulatory Motif
parms

	wc += gu;


descr

	h5(minlen=5, maxlen=6, mispair=1)

		ss(minlen=0, maxlen=6)

		h5(minlen=5, maxlen=6, mispair=1)

			ss(minlen=0, maxlen=2)

			h5(minlen=5, maxlen=8, mispair=1)

				ss(minlen=3, maxlen=8)

			h3

			h5(minlen=5, maxlen=8, mispair=1)

				ss(minlen=3, maxlen=5)

			h3

			ss(minlen=0, maxlen=5)

		h3

		ss(minlen=0, maxlen=6)

	h3

	ss(minlen=2, maxlen=5)

	h5(minlen=5, maxlen=6, mispair=1)

		ss(minlen=3, maxlen=8)

	h3

	ss(minlen=3, maxlen=10)

	ss(seq="^ATG$")

	
Description Internal mRNA ribosome binding is a mechanism of translation initiation alternative to the conventional 5'-cap dependendent ribosome scanning mechanism. The internal initiation mechanism, first observed in picornavirus, is also found in some cellular mRNAs, such as human immunoglobulin heavy chain binding protein (BiP) mRNA, Antennapedia mRNA of drosophila and FGF-2 mRNA. This mechanism may be advantageous for specific translation of mRNAs during cell cycle when underphosphorilated eIF-4F prevents conventional translation initiation. The internal initiation mechanism is dependent on a cis-acting element, defined as internal ribosome entry site (IRES), located in the 5'UTR region of the mRNA. Comparative analysis of known IRES in some cellular mRNAs identified a common structural motif forming a Y-type stem-loop structure followed by the AUG triplet or followed by additional stem-loop structures and the AUG triplet.
References Le SY, and Maizel JV
A common RNA structural motif involved in the internal initiation of translation of cellular mRNAs.
Nucleic Acids Res 1997; 25(2), 362-69   PubMed 


Department of Biological Science and Technology, Institute of Bioinformatics, National Chiao Tung University, Taiwan
Contact with Dr. Hsien-Da Huang