What makes sperm do its job?

By Kirsty Horsey

Progress Educational Trust

23 July 2002

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[BioNews, London] UK Researchers have discovered a molecule in sperm cells that triggers fertilisation. Professor Tony Lai and his team at the University of Wales, Cardiff, announced last week that they have isolated a 'sperm factor' gene that makes a protein which causes egg cells to begin to divide and develop into an embryo when penetrated by a sperm.

The protein, called PLC-zeta, causes surges in the level of calcium in the egg during fertilisation. Cell division triggered by calcium surges had already been observed in fertilised eggs during in vitro fertilisation (IVF) procedures, but it was not known how these surges were triggered by sperm.

The scientists, who reported their findings in the online version of the journal Development, believe that men who do not possess a functioning copy of the gene could be infertile. As such, the new research could have implications for the treatment of male infertility. Knowing exactly what causes fertilisation and embryo development to begin may also help new contraceptives to be developed.

PLC-zeta may also benefit cloning and stem cell technology by replacing the electrical impulses currently being used to cause embryos created by nuclear transfer to begin development. When the research team introduced the protein to eggs in the laboratory they began to divide, continuing development until the blastocyst stage.

Noting that 277 eggs were used to create Dolly the cloned sheep, Professor Lai said that using PLC-zeta 'would improve the efficiency of the [cloning] process, allowing more stem cells to be produced and enhancing our ability to use them in treatment'.

Reproduced with permission from BioNews, an email and online sources of news, information and comment on assisted reproduction and genetics.