Amazing stuff!
I remember way back then when some feminists and some female women's rights activists mocked/dismissed men as mere, dispensable sperm providers.
"Sperm have long been thought of as streamlined DNA delivery vehicles, carrying little more than a father’s genes to the egg. But a new study shows that in mice, sperm may transmit the father’s influence in another way: During their passage through the epididymis, the coiled tube where they mature after leaving the testes, sperm pick up messenger RNAs (mRNAs)—RNA transcripts of genes that contain the genetic instructions for making proteins. And these mRNAs seem to be transferred to the fertilized egg, a team reports this week in Nucleic Acids Research.
Researchers already knew sperm ferry small RNAs, RNA fragments that can silence gene expression and have been implicated in transmitting the effects of paternal diet, stress, and exercise to offspring. But mRNAs could be a far more direct route for paternal influence ... The work doesn’t prove these mRNAs from sperm actually function in embryos, she noted, but the discovery of unexpected cargo is “potentially very significant.”"
"... The researchers also found that some mRNAs present in mature sperm are absent from unfertilized eggs, but appear in zygotes after fertilization—suggesting sperm deliver these transcripts to the embryo, ... Because environmental conditions can trigger mRNA production in the father, the observed mRNA transfer “really establishes a mechanism for how the environment can directly influence sperm to then potentially influence the next generation,” ...
the researcher injected long RNA sequences into parthenotes—mouse eggs triggered to divide and develop without sperm. They found the injections shifted the cells’ gene expression to resemble normally fertilized embryos. (They team used RNAs longer than 200 nucleotides, but not mRNA ... The results suggest large RNAs from sperm “can do something after fertilization to regulate embryonic gene expression,” ...
The mechanism may not be limited to mice. The team also sequenced mRNAs from mature human sperm and found counterparts to many mRNAs in mouse sperm, suggesting humans may also deliver RNA messages to their offspring this way."
From the abstract:
"The epididymis plays a critical role in promoting sperm maturation, including remodeling the sperm RNA payload. While small RNAs have been extensively studied in this context, the epididymal contribution to larger sperm RNAs, such as messenger RNAs (mRNAs), remains underexplored. This is largely due to the translational quiescence of mature spermatozoa and the hypothesis that these RNAs are residual by-products of spermatogenesis.
Yet, mRNAs carried by sperm have been detected in the zygote, indicating they may act beyond fertilization. However, whether epididymal somatic cells contribute mRNAs to sperm, as they do small RNAs, has not been experimentally examined. Here, we provide a comprehensive analysis of the mRNA landscape of mouse sperm, epithelial cells, and extracellular vesicles (EVs) isolated from the proximal (caput) and distal (cauda) epididymis.
Through this analysis and sperm-EV co-incubation experiments, we demonstrate the transfer of mRNAs from epididymal EVs to sperm.
Further, through sperm RNA microinjection into zygotes, we uncover gene regulation in the early embryo driven by the introduction of sperm RNAs, specific to >200-nucleotide RNA species.
These findings reveal the dynamic mRNA profile of sperm that is delivered to the egg and demonstrate that RNA species beyond small RNAs are capable of influencing preimplantation embryo gene expression."
Sperm carry unexpected genetic messages "Maturing mouse sperm get loaded with full-length messenger RNAs that are transferred to fertilized egg, suggesting a new route for paternal influence"
Epididymal extracellular vesicles harbor and convey mRNA to sperm for transfer to zygotes (open access) [This is a long research article!]
Graphical abstract
No comments:
Post a Comment