And if you're at @edrc2025.bsky.social, come check out Alicia Donoghue present this work in the signalling session tomorrow (Friday) 15:00!

Thanks! It's been a really fun project and between your work and ours, highlights how conserved male germ cell biology is...

😵‍💫

Plenty more in the manuscript - read it here:
www.biorxiv.org/content/10.1...
This is the work of @diegosainzdelamaza.bsky.social, started by Holly Jefferson a few years ago, with help from undergraduate students, Sonia and Celine.
And thanks to so many colleagues for advice, help and reagents!

Finally, we ask how the soma ensures it produces enough lactate to support the germline. We show it's a very delicate balance and the somatic cells are careful not to use pyruvate in their own mitochondria; in other words, they exclusively dedicate the glycolytic pathway to support the germline.

One for the 🪰 nerds: we found a previously uncharacterised transporter that mediates lactate transport from somatic cells to the germline, so we get to name it. We called it milkman 🥛.

Excitingly, germ cells consume lactate (but don't produce it) - knocking down the enzyme that interconverts lactate and pyruvate, Ldh, in germ cells, results in lactate accumulation (contrary to the somatic cells which produce lactate)

So what do the somatic cells provide? We used fluorescent reporters for metabolites and we see that they produce lactate. Knocking down the enzyme that produces lactate from the glycolytic product pyruvate, Ldh, in somatic cells causes germ cells to die.

If we block glycolysis in somatic cells, we find that germ cells start dying. There's always some death in the germline, but almost twice as much when we knock down glycolytic genes in somatic cells. Knock down in the germ cells themselves has no effect - they don't break down sugars themselves.

We show that somatic cells of the testis take up circulating sugars and break them down through glycolysis.
But germ cells don't express the genes needed for glycolysis.

So where do germ cells get their nutrients from? And how does the soma make sure they get enough?
That's what we answer here.

It has been known for a long time that male germ cells are enveloped by somatic cells and lose access to nutrients from blood circulation. Not just in mammals, but even in flies (where blood is called haemolymph) as shown by @tanentzapflab.bsky.social.

yes - you should talk to Inês in Vil's lab, she's really the one who went through it all.

We've been using a tip washer to reuse tips for most things - most of what we do is immunohistochemistry. We've been a bit more reluctant than the fish floor to use them for molecular biology work, but it doesn't seem to affect their gels so maybe we'll start using washed tips for that too.