1. Assembly of the ribonucleoprotein complex containing the mRNA of the β-subunit of the mitochondrial H+-ATP synthase requires the participation of two distal cis-acting elements and a complex set of cellular trans-acting proteins
- Author
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José M. Izquierdo, José M. Cuezva, Javier Ricart, Carlo Maria Di Liegro, Ricart, J., Izquierdo, J., Di Liegro, C., and Cuezva, J.
- Subjects
Male ,Translation ,Blotting, Western ,Mitochondria, Liver ,RNA-binding protein ,Biochemistry ,Reticulocyte ,Pregnancy ,Polysome ,P-bodies ,medicine ,Animals ,Oxidative phosphorylation ,RNA, Messenger ,Rats, Wistar ,3' Untranslated Regions ,Molecular Biology ,In Situ Hybridization ,Messenger RNA ,ATP synthase ,biology ,Three prime untranslated region ,RNA-Binding Proteins ,RNA ,Cell Biology ,Immunohistochemistry ,Rats ,Proton-Translocating ATPases ,medicine.anatomical_structure ,biology.protein ,mRNA localization ,Female ,Research Article - Abstract
The mRNA encoding the beta-subunit of the mitochondrial H(+)-ATP synthase (beta-F1-ATPase) is localized in an approx. 150 nm structure of the hepatocyte of mammals. In the present study, we have investigated the cis- and trans-acting factors involved in the generation of the ribonucleoprotein complex containing beta-F1-ATPase mRNA. Two cis-acting elements (beta1.2 and 3'beta) have been identified. The beta1.2 element is placed in the open reading frame, downstream of the region encoding the mitochondrial pre-sequence of the protein. The 3'beta element is the 3' non-translated region of the mRNA. Complex sets of proteins from the soluble and non-soluble fractions of the liver interact with the beta1.2 and 3'beta elements. A soluble p88, present also in reticulocyte lysate, displays binding specificity for both the cis-acting elements. Sedimentation and high-resolution in situ hybridization experiments showed that the structure containing the rat liver beta-F1-ATPase mRNA is found in fractions of high sucrose concentration, where large polysomes sediment. Treatment of liver extracts with EDTA promoted the mobilization of beta-F1-ATPase mRNA to fractions of lower sucrose concentration, suggesting that the structure containing beta-F1-ATPase mRNA is a large polysome. Finally, in vitro reconstitution experiments with reticulocyte lysate, using either the full-length, mutant or chimaeric versions of beta-F1-ATPase mRNA, reveal that the assembly of the beta-F1-ATPase mRNA polysome requires the co-operation of both the cis-acting mRNA determinants. The present study illustrates the existence of an intramolecular RNA cross-talking required for the association of the mRNA with the translational machinery.
- Published
- 2002