Molecular basis for maternal inheritance of human mitochondrial DNA.
Level 5 - mechanism / opinion, no new human data
Bench research and mechanistic laboratory analysis of human sperm cells with no clinical trial data.
PubMed 37723262 · doi:10.1038/s41588-023-01505-9
What was done
Investigated the molecular mechanism preventing paternal mitochondrial DNA (mtDNA) transmission in humans by analyzing human spermatozoa and spermatogenesis stages for the presence of intact mtDNA and mitochondrial transcription factor A (TFAM).
What was found
Mitochondria in human spermatozoa were devoid of intact mtDNA and lacked TFAM. During spermatogenesis, sperm cells expressed an isoform of TFAM retaining the mitochondrial presequence; phosphorylation of this presequence prevented mitochondrial import and directed TFAM to the spermatozoon nucleus. This relocalization directly correlated with the elimination of mtDNA. The abstract reports no quantitative values.
Why it matters
Provides a molecular mechanism for strict maternal inheritance of mtDNA in humans, showing that paternal mtDNA is eliminated during spermatogenesis via TFAM relocalization rather than solely degraded inside the oocyte after fertilization.
Limits
No sample sizes, donor counts, or quantitative measurements are provided in the abstract. As a laboratory-based mechanistic study, potential variability across broader human populations or clinical fertility settings is not addressed in the abstract.
Cited by
- supports All mitochondria in the human body are derived exclusively from the maternal egg.