Fig. 2

Identification of an alternative protein in the mtDNA-encoded nd4 gene. A The MTALTND4 ORF and its DNA and protein sequences (antigenic sequence underlined), as well as its protein structure prediction. This ORF is frameshifted by 2 nucleotides relative to ND4 reading frame. B MTALTND4 detected by western blotting in HeLa and HEK-293 T cells—a protein lysate of HeLa cells transfected with the coding sequence of the corresponding MTALTND4 protein with a FLAG tag was used as a positive control for MTALTND4. C MTALTND4, mtDNA-encoded cytochrome c oxidase subunit I (CO1), nuclear-encoded Actin and nuclear-encoded mitochondrial ATP5 in HeLa (control) and HeLa cells treated with chloramphenicol (cam) or actinonin (act), and in HeLa Rho0 cells. D Detection of MTALTND4 and nuclear-encoded mitochondrial ATP5 by immunofluorescence in HeLa cells treated with chloramphenicol. E Multiple peptide sequence alignment in five primate species. Black background for residues conserved in all species and gray for residues conserved in 4 out of 5 species. Asterisk indicates a stop codon. F Detection of MTALTND4 and nuclear-encoded mitochondrial ATP5 by immunofluorescence in HeLa cells. G Detection of MTALTND4 and nuclear-encoded mitochondrial ATP5 by western blotting in human plasma