cis-acting sequences and trans-acting factors in the localization of mRNA for mitochondrial ribosomal proteins.
mRNA localization is a conserved post-transcriptional process crucial for a variety of systems. Although several mechanisms have been identified, emerging evidence suggests that most transcripts reach the protein functional site by moving along cytoskeleton elements. We demonstrated previously that mRNA for mitochondrial ribosomal proteins are asymmetrically distributed in the cytoplasm, and that localization in the proximity of mitochondria is mediated by the 3'-UTR. Here we show by biochemical analysis that these mRNA transcripts are associated with the cytoskeleton through the microtubule network. Cytoskeleton association is functional for their intracellular localization near the mitochondrion, and the 3'-UTR is involved in this cytoskeleton-dependent localization. To identify the minimal elements required for localization, we generated DNA constructs containing, downstream from the GFP gene, deletion mutants of mitochondrial ribosomal protein S12 3'-UTR, and expressed them in HeLa cells. RT-PCR analysis showed that the localization signals responsible for mRNA localization are located in the first 154 nucleotides. RNA pull-down assays, mass spectrometry, and RNP immunoprecipitation assay experiments, demonstrated that mitochondrial ribosomal protein S12 3'-UTR interacts specifically with TRAP1 (tumor necrosis factor receptor-associated protein1), hnRNPM4 (heterogeneous nuclear ribonucleoprotein M4), Hsp70 and Hsp60 (heat shock proteins 70 and 60), and alpha-tubulin in vitro and in vivo.
Russo
Annapina
A
Dipartimento di Biochimica e Biotecnologie Mediche, Università Federico II, Via Sergio Pansini 5, Napoli 80131, Italy.
Cirulli
Claudia
C
Amoresano
Angela
A
Pucci
Pietro
P
Pietropaolo
Concetta
C
Russo
Giulia
G
D020413:3' Untranslated Regions; D018834:Chaperonin 60 / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000737:chemistry; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006367:HeLa Cells; D034761:Heterogeneous-Nuclear Ribonucleoprotein Group M / Q000378:metabolism; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D014404:Tubulin / Q000378:metabolism
D020413:3' Untranslated Regions; D018834:Chaperonin 60; C440104:HNRNPM protein, human; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D034761:Heterogeneous-Nuclear Ribonucleoprotein Group M; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C092306:TRAP1 protein, human; D014404:Tubulin; C112310:mitochondrial ribosomal protein S12; D049452:Green Fluorescent Proteins