PMID- 14585982
OWN - NLM
STAT- MEDLINE
DCOM- 20031210
LR  - 20210526
IS  - 0270-7306 (Print)
IS  - 1098-5549 (Electronic)
IS  - 0270-7306 (Linking)
VI  - 23
IP  - 22
DP  - 2003 Nov
TI  - The 5' untranslated region and Gag product of Idefix, a long terminal 
      repeat-retrotransposon from Drosophila melanogaster, act together to initiate a 
      switch between translated and untranslated states of the genomic mRNA.
PG  - 8246-54
AB  - Idefix is a long terminal repeat (LTR)-retrotransposon present in Drosophila 
      melanogaster which shares similarities with vertebrates retroviruses both in its 
      genomic arrangement and in the mechanism of transposition. Like in retroviruses, 
      its two LTRs flank a long 5' untranslated region (5'UTR) and three open reading 
      frames referred to as the gag, pol, and env genes. Here we report that its 5'UTR, 
      located upstream of the gag gene, can fold into highly structured domains that 
      are known to be incompatible with efficient translation by ribosome scanning. 
      Using dicistronic plasmids analyzed by both (i) in vitro transcription and 
      translation in rabbit reticulocyte or wheat germ lysates and (ii) in vivo 
      expression in transgenic flies, we show that the 5'UTR of Idefix exhibits an 
      internal ribosome entry site (IRES) activity that is able to promote translation 
      of a downstream cistron in a cap-independent manner. The functional state of this 
      novel IRES depends on eukaryotic factors that are independent of their host 
      origin. However, in vivo, its function can be down-regulated by trans-acting 
      factors specific to tissues or developmental stages of its host. We identify one 
      of these trans-acting factors as the Gag protein encoded by Idefix itself. Our 
      data support a model in which nascent Gag is able to block translation initiated 
      from the viral mRNA and thus its own translation. These data highlight the fact 
      that LTR-retrotransposons may autoregulate their replication cycle through their 
      Gag production.
FAU - Meignin, Carine
AU  - Meignin C
AD  - Unite INSERM U384, Service de Bacteriologie-Virologie, Faculte de Medecine, 28 
      Place Henri Dunant, 63000 Clermont-Ferrand, France.
FAU - Bailly, Jean-Luc
AU  - Bailly JL
FAU - Arnaud, Frederick
AU  - Arnaud F
FAU - Dastugue, Bernard
AU  - Dastugue B
FAU - Vaury, Chantal
AU  - Vaury C
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Mol Cell Biol
JT  - Molecular and cellular biology
JID - 8109087
RN  - 0 (5' Untranslated Regions)
RN  - 0 (RNA Caps)
RN  - 0 (RNA, Messenger)
RN  - 0 (Retroelements)
SB  - IM
MH  - 5' Untranslated Regions
MH  - Animals
MH  - Animals, Genetically Modified
MH  - Drosophila melanogaster/*genetics
MH  - Gene Silencing
MH  - Genes
MH  - Genes, Insect
MH  - Genes, gag
MH  - Lac Operon
MH  - Models, Genetic
MH  - Protein Biosynthesis
MH  - RNA Caps/genetics
MH  - RNA, Messenger/*genetics
MH  - Retroelements/*genetics
MH  - *Terminal Repeat Sequences
PMC - PMC262410
EDAT- 2003/10/31 05:00
MHDA- 2003/12/12 05:00
PMCR- 2003/11/01
CRDT- 2003/10/31 05:00
PHST- 2003/10/31 05:00 [pubmed]
PHST- 2003/12/12 05:00 [medline]
PHST- 2003/10/31 05:00 [entrez]
PHST- 2003/11/01 00:00 [pmc-release]
AID - 0915 [pii]
AID - 10.1128/MCB.23.22.8246-8254.2003 [doi]
PST - ppublish
SO  - Mol Cell Biol. 2003 Nov;23(22):8246-54. doi: 10.1128/MCB.23.22.8246-8254.2003.