Gene of the Month - Panton-Valentine leukocidin

To celebrate Valentine’s day, for this episode'sGene of the Monthwe’ve picked the most romantic molecule we could find - Panton-Valentine leukocidin, or PVL. Unlike flowers, chocolate or sexy underwear, this is definitely not a gift that you’ll want to receive from your beloved, as it’s a potent bacterial toxin.

PVL was first discovered by Belgian researcher Honore Van de Velde in 1894, who was searching for chemicals produced by bacteria that could damage white blood cells, or leukocytes - important cells in the immune system. But it’s named after It’s named after Philip Panton and Francis Valentine, two scientists working in the 1930s who discovered that it was produced by strains of Staphylococcus aureus bacteria that caused the most severe infections in rabbits.

Further research revealed that PVL is made up of two proteins LukS-PV and LukF-PV, encoded by two separate genes. Together, they form a small pore in the wall of immune cells, causing their insides to leak out - something known as cell lysis. The contents of these sadly exploded cells than acts as tasty nutrients to feed the bacteria as the infection spreads. Intriguingly, the genes seem to have originally come from tiny viruses that infect bacteria, called bacteriophages.

Just as Panton and Valentine found that PVL-producing Staph. aureus produce nasty infections in bunnies, they also bring a lot of harm to humans, causing a type of necrotising pneumonia that can kill up to three quarters of patients. PVL-producing bacterial strains have also been pinpointed in many fatal bacterial outbreaks.

Given that PVL is found in the majority of antibiotic resistant Staph. aureus - the infamous MRSA superbugs - there’s a lot of interest in developing new treatments that block the toxin, which could combat the growing problem of antibiotic resistance. So although it may have Valentine in its name, PVL definitely isn’t something you’ll want to give the one you love this February.