The sperm mitochondria-specific translocator has a key role in maternal mitochondrial inheritance

Abstract

AbstrctThe mechanism of maternal mitochondrial inheritance in animals involves the selective elimination of sperm mitochondria by the elimination factor of the egg and the sperm mitochondria-specific factor. In vitro fertilization using sperm from congenic mice incorporating heterogeneous mitochondrial DNA (mtDNA) showed that the number of PCR positives of sperm mtDNA in two-cell embryos was significantly increased following sperm incubation with anti-tpis, anti-Tom22 and anti-Tom40 antibodies. The treatment of fertilized eggs with EGTA and endonuclease inhibitors increased the sperm mtDNA levels. We conclude that the elimination factor, which is probably an endonuclease, is selectively received by the tpis protein of the sperm mitochondrial outer membrane within the egg. It is then transported into the sperm mitochondria by Tom22 and Tom40, where it destroys the sperm mtDNA, establishing the maternal inheritance of mtDNA.3

Nuclear–mitochondrial genomic profiling reveals a pattern of evolution in epithelial ovarian tumor stem cells

“…We further conducted a chase-back study towards tracing the origin of these variations. Normal tissue sample of the same patient was unavailable; hence, a peripheral blood sample from the son was obtained -valid as mtDNA is almost exclusively maternally inherited (Hayashida et al, 2005). Comparison of profiles revealed only one mtDNA sequence variation between the son and the tumor cells of the patient (310 insC instead of 310 insCC - Table 2).…”

Hybrid male sterility is caused by mitochondrial DNA deletion

“…The dissection of testis and mature ovary from mice killed through cervical dislocation and isolation of cytosol and mitochondria were performed as previously described [3].…”

“…Trypsination of isolated testis mitochondria was performed as previously described [3]. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 6 TdT-mediated dUTP nick end labeling (TUNEL) assay After deparaffinizing and rehydrating the fixed and paraffin-embedded sections of testis, the sections were treated with 20 μg / ml protenase K at room temperature for 15 minutes followed by labeling with fluorescein-dUTP and terminal deoxynucleotidyl transferase (TdT) 37 ℃ for 2 hours.…”

“…Western immunoblotting by SDS-PAGE of ovary and testis proteins with anti-Spag1-2 polyclonal antibody and anti-Eri15 polyclonal antibody was performed as previously described [3,4]. Anti-β-actin monoclonal antibody (Sigma) and anti-VDAC1/porin polyclonal antibody (abcam) were used as the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 8 loading control of cytosol and mitochondria respectively.…”

“…We previously reported that maternal mitochondrial DNA (mtDNA) inheritance of the mouse is through selective sperm mtDNA elimination based on the sperm-specific translocator of the mitochondrial outer membrane (Spag1-1), two egg factors of the system-specific endonuclease (Eri15) and the system-specific chaperone (Spag1-2 or 1-3) [3,4]. In the male germ cells the expression of Spag1-2 (or 1-3) is possibly suppressed by epistatic gene(s).…”