The proteins which attract sperm to egg


The protein which attracts the sperm to egg was discovered almost a decade ago. Now the protein which works to attract egg to sperm has also been discovered. In 2005 a group of Japanese scientists discovered the Izumo protein, named after a Japanese marriage shrine. This protein is on the surface of the sperm and recognizes the egg so the two can fuse to form an embryo. The new protein, which works to fuse egg to sperm has been named Juno by researchers in the UK who named the protein after the Roman goddess of fertility and marriage.

Juno, meet Izumo

The meeting of Izumo and Juno is the first step in procreation. “We have solved a long standing mystery in biology by identifying the molecules displayed on the sperm and egg which must bind each other at the moment we were conceived. Without this essential interaction, fertilization just cannot happen,” according to senior author Dr. Gavin Wright who leads the Institute’s Cell Surface Signalling Laboratory at the Wellcome Trust Sanger Institute in Cambridge. The discovery should lead to important improvements in fertility treatments.

Juno is essential for female fertility

The researchers engaged in a bit of hide-and-go-seek to find the protein. First, they created an artificial Izumo and used it to find binding partners on the surface of a mouse egg. The protein they found they called Juno. Then they created a female mice lacking the Juno protein. These mouse were infertile.

One and done

In addition, researchers also discovered that the protein is discarded and shed once its usefulness is gone. Eggs shed Juno to ensure that only one sperm fuses to the one egg. Within 40 minutes of fertilization, all evidence of Juno is gone from cell surfaces.

Source: MedicalNewsToday, Nature


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