An expression vector adapted to the efficient and stable supply of a protein within the mitochondria of a mammalian cell, wherein said vector comprises: - a mitochondrial targeting nucleic acid sequence (MTS nucleic acid sequence), - a nucleic acid sequence encoding said protein according to the universal genetic code (CDS sequence), and - a 3 'nucleic acid sequence, which is located 3' of said MTS nucleic acid sequence and said CDS, in the that said MTS nucleic acid sequence is: - the cDNA sequence of an MTS of an mRNA encoded in the nucleus and directed to the mitochondria, or - a conservative fragment of said cDNA sequence, which is derived therefrom by deletion of one or several nucleotides, but it has retained a mitochondrial targeting function, in which said 3 'nucleic acid sequence is: - the cDNA sequence of the 3'UTR sequence of an mRNA encoded in the nucleus and directed to the mitochondria, or - a conservative fragment of said cDNA sequence, which is derived therefrom by deletion of one or more nucleotides and which, when replacing the wild type 3'UTR of said mRNA encoded in the nucleus and directed to the mitochondria, continues to allow mitochondrial targeting of the resulting mRNA, in which said CDS is a nucleic acid encoding a mitochondrial protein and in which said vector does not comprise any sequence that would be identical to: - the 3'UTR of a naturally occurring mRNA that is an mRNA transcribed in the nucleus but not directed to the mitochondria, or - the cDNA sequence of said 3'UTR sequence, or - a DNA sequence transcribed in said 3'UTR of origin mRNA natural, so that said vector does not use a post-translational import route, but instead uses a co-induced import route from the nucleus to said mitochondria.Un vector de expresión adaptado al suministro eficiente y estable de una proteína al interior de la mitocondria de una célula de mamífero, en el que dicho vector comprende: - una secuencia de ácido nucleico de direccionamiento a la mitocondria
