Intermittent rivers and ephemeral streams (IRES) compose the majority of draining networks on Earth, supporting a unique fraction biodiversity. Despite their high ecological value, IRES are increasingly threatened by global change require appropriate biomonitoring restoration tools. However, indices indicators used in routine programs often confounded drying effects. This occurs because most po...

Internal initiation of protein synthesis in eukaryotes is accomplished by recruitment of ribosomes to structured internal ribosome entry sites (IRESs), which are located in certain viral and cellular messenger RNAs. An IRES element in cricket paralysis virus (CrPV) can directly assemble 80S ribosomes in the absence of canonical initiation factors and initiator tRNA. Here we present cryo-EM stru...

Transport of the essential amino acids arginine and lysine is critical for the survival of mammalian cells. The adaptive response to nutritional stress involves increased translation of the arginine/lysine transporter (cat-1) mRNA via an internal ribosome entry site (IRES) within the mRNA leader. Induction of cat-1 IRES activity requires both translation of a small upstream open reading frame (...

The positive-stranded RNA genome of Plautia stali intestine virus (PSIV) has an internal ribosome entry site (IRES) in an intergenic region (IGR). The IGR-IRES of PSIV initiates translation of the capsid protein by using CAA, the codon for glutamine. It was previously reported (J. Sasaki and N. Nakashima, J. Virol. 73:1219-1226, 1999) that IGR-IRES extended by several nucleotides into the capsi...

GB virus B (GBV-B) is a recently discovered hepatotropic flavivirus that is distantly related to hepatitis C virus (HCV). We show here that translation of its polyprotein is initiated by internal entry of ribosomes on GBV-B RNA. We analyzed the translational activity of dicistronic RNA transcripts containing wild-type or mutated 5' nontranslated GBV-B RNA (5'NTR) segments, placed between the co...

The internal ribosome entry site (IRES) element located at the 5'untranslated genomic region of various RNA viruses mediates cap-independent initiation of translation. Picornavirus IRES activity is highly dependent on both its structural organization and its interaction with host factors. Small molecules able to interfere with RNA function are valuable candidates for antiviral agents. Here we s...

Hepatitis C virus (HCV) translation is mediated by an IRES structure. Instead of a poly(A) tail, the 3' end of the genome contains a tripartite 3'NTR composed of a non-conserved region, a polypyrimidine tract and a highly conserved stretch of 98 nt, termed the 3'X region. Using a set of bicistronic recombinant DNA constructs expressing two reporter genes separated by the HCV IRES, it was determ...

Translation of Giardiavirus (GLV) mRNA is initiated at an internal ribosome entry site (IRES) in the viral transcript. The IRES localizes to a downstream portion of 5' untranslated region (UTR) and a part of the early downstream coding region of the transcript. Recent studies indicated that the IRES does not require a pre-initiation complex to initiate translation but may directly recruit the s...

Mammalian eukaryotic initiation factor 4GI (eIF4GI) may be divided into three similarly sized regions. The central region (amino acids [aa] 613 to 1090) binds eIF3, eIF4A, and the encephalomyocarditis virus (EMCV) internal ribosomal entry site (IRES) and mediates initiation on this RNA. We identified the regions of eIF4GI that are responsible for its specific interaction with the IRES and that ...

Rhopalosiphum padi virus (RhPV) is one of several picorna-like viruses that infect insects; sequence analysis has revealed distinct differences between these agents and mammalian picornaviruses. RhPV has a single-stranded positive-sense RNA genome of about 10 kb; unlike the genomes of Picornaviridae, however, this genome contains two long open reading frames (ORFs). ORF1 encodes the virus nonst...