Localisation of a reporter transcript by the c-myc 3'-UTR is linked to translation.
The 3'-untranslated region of c-myc mRNA contains a perinuclear localisation signal which is sufficient to target beta-globin coding sequences. The link between perinuclear mRNA localisation and translation has been investigated using cells transfected with chimeric gene constructs in which globin reporter sequences were linked to the c-myc 3'-untranslated region and the iron-responsive element from ferritin mRNA. Iron supplementation of the medium promoted translation of the chimeric mRNA as assessed by its presence in polysomes; in situ hybridisation showed that the mRNA was localised around the nucleus. Treatment with the iron chelator desferrioxamine for 16 h prevented both translation and mRNA localisation. In controls where the expressed mRNA lacked the iron-responsive element desferrioxamine had no effect upon localisation. In contrast, arrest of on-going global translation by puromycin treatment had no effect on mRNA localisation. The data suggest that if initiation of translation of a mRNA containing the c-myc localisation signal is prevented in some way then localisation does not occur, whereas once the mRNA has been localised further translation is not required to maintain mRNA localisation.
Dalgleish
G D
GD
Intracellular Targeting Group, Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK.
Veyrune
J L
JL
Accornero
N
N
Blanchard
J M
JM
Hesketh
J E
JE
D020413:3' Untranslated Regions / Q000502:physiology*; D000818:Animals; D016466:CHO Cells; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D006224:Cricetinae; D003676:Deferoxamine / Q000494:pharmacology; D005293:Ferritins / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter; D005914:Globins / Q000235:genetics; D007501:Iron / Q000502:physiology; D014176:Protein Biosynthesis / Q000187:drug effects; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects
D020413:3' Untranslated Regions; D002614:Chelating Agents; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D005914:Globins; D005293:Ferritins; D007501:Iron; D003676:Deferoxamine