Figure 2

143B cells and 143B cells harbouring different mtDNA genotypes. (a) Tumour progression for 143B¹⁰⁰, 143B⁰, 143B^NSC and 143B^GBM cells; (b) mtDNA copy number in 143B¹⁰⁰, 143B⁰, 143B^NSC and 143B^GBM cells, and their respective tumours at early and late progression; (c) PCR-gel of mouse mtDNA in 143B⁰ tumours. Human (h.)β-globin and mouse (m.)β-actin demonstrate the presence of human and mouse chromosomal DNA, respectively, while m.mtDNA shows the presence of mouse mtDNA; (d) mouse mtDNA in 143B⁰ tumours at early progression, late progression, cells isolated from late progression tumours and after further cultured in vitro (143B^mus clones), and tumours from re-inoculated 143B^mus cells; (e) tumour progression for isolated 143B⁰ tumour cells post-reinoculation (143^mus reinoculated tumour formed); (f) 143B¹⁰⁰, 143B^GBM and 143B^NSC tumours at early and late progression underwent immunoprecipitation to assess the levels of enrichment for 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC), which are indicative of active de novo and transient DNA methylation, respectively, and mtDNA copy number to determine the replicative efficiency (*P<0.05; ***P<0.001).