The symbiotic bacterium "Wolbachia" is said to be infected with about half of the insects.By entering the female egg of the infected host, it is transmitted to the next generation and does not propagate from the male host.Wolbachia is said to manipulate the host with various strategies, such as parthenogenesis of females and prevention of fertilization by mating with uninfected females, in order to gain an advantage in the reproduction of infected females. ..However, it was unclear why Wolbachia could do this.
Professor Daisuke Yamamoto of Tohoku University and major academic researchers have elucidated the mechanism of host manipulation by working the DNA fragment of Wolbachia in infertile Drosophila to cause the same effect as infection.The research results were published in the online version of the American scientific journal "Current Biology".
One of the mutants of Drosophila is the Sex-lethal (Sxl) mutant.This is because the cells that make eggs are lost from the ovaries and cannot make eggs, but it is known that when they are infected with Wolbachia, eggs will be made again.
The research group studied which of the approximately 1200 genes in Wolbachia cause this effect.First, when the DNA of Wolbachia was fragmented and applied to the reproductive stem cells of the normal female ovary of Drosophila, one species was found that lost its function.As a result of working this DNA fragment on females of infertile Sxl mutants, the lost reproductive stem cells are said to have been restored.In other words, this DNA fragment alone was able to reproduce the host manipulation of Wolbachia.
The gene contained in this DNA fragment was named "TomO" by the research group.As the research progressed, it became clear that the "TomO protein" produced from TomO is secreted from Wolbachia and acts on a gene called nanos in the host to increase the Nanos protein and restore germ stem cells.
Overexpression of the Nanos protein instead of TomO has also been shown to restore germ stem cells to the Sxl mutant. Since Nanos has the function of maintaining mammalian reproductive stem cells, the results of this research show not only the elucidation of the mechanism of host manipulation by bacteria, but also a new approach that leads to the improvement of mammalian reproductive function using TomO.
