Fig. 9

Human YME1L1 inactivation leads to increased numtogenesis. TCGA tumor sample data used in this study were screened for mutations in the YME1L1 gene. A total of 24 mutations (five exonic, 17 intronic, and two in the 3′ UTR) in YME1L1 were identified. All five exonic mutations were frameshift mutations. a, b The position of these mutations in the YME1L1 gene (a) and protein (b). c The total colorectal cancer samples available in TCGA database were analyzed on 4 April 2016 for mutations in Yme1L1 and their types determined. d Mutations in Yme1L1 in other cancers were also analyzed using the cBioPortal database. Altered frequency of Yme1L1 mutations in different cancer types are represented. e mtDNA content in nuclear fractions, i.e., NUMT accumulation was analyzed in wild-type (WT) and YME1L1 knockout (Yme1L1-KO) human cell lines. NUMT accumulation was about fourfold increased in YME1L1-KO cells compared with wild-type cells. Data are expressed as mean ± standard error of the mean (sem); *P < 0.05, Student’s t-test. f, g The yeast PTY33-Yme1-1 (ρ+, TRP1) strain was transformed with empty plasmid and plasmids expressing yYme1 and hYme1L1 with URA marker as indicated. Transformed cell colonies were selected by synthetic dropout medium lacking URA. f Whole cell lysate from the Yme1-1 vector, Yme1-1 yYme1, and Yme1-1 hYme1L1 strains was subjected to SDS-PAGE and western blotting was performed with antibodies against hYme1L1 and β-actin. g Yme1-1 vector, Yme1-1 yYme1, and Yme1-1 hYme1L1 cells were spread on plates lacking tryptophan; the experiment was performed three times in triplicate. Data are expressed as mean ± sem; *P < 0.05, Student’s t-test