Researchers reveal how sperm fertilizes an egg; uses tiny harpoons!

In a new findings, researchers have decoded how sperm fertilizes an egg to make women pregnant. After 14 year long research, scientists from the University of Virginia have revealed that protein that resides in the head of sperm and acts like a harpoon which enables sperm to attach itself to the egg and fertilize it. Study authors say, they have discovered a tiny spiky filament like structure which helps in joining sperm head with its target.

Lead study author John Herr said that the discovery has led to new set of notions and will change previous hypothesis about the events that occur during fertilization process. He further added that one of the major proteins that is abundant in the acrosome found in the anterior region of the sperm head is crystallizing into filaments and is aiding sperm in penetrating the egg.

Herr had discovered protein called SLLP1 long ago in his lab. SLLP1 protein belongs to the family of protein found in acrosome which forms harpoon-like structure. Although, Herr had discovered the protein but was unable to determine its shape and the mechanism by which it facilitated fertilization. Then he took the help of Wladek Minor’s lab, also at the University of Virgina to show that the protein has spiky filament like structure at the sperm head.

To determine the shape of SLLP1, Minor’s team used static crystal to capture the protein. To prevent decay of protein, researchers cooled it down and X-rays were shooted on those static crystals.  With the help of computational models and refraction property of X-rays, researchers identified the shape of SLLP1. It is the same property of X-rays which is used in sonar application like mapping a shipwreck or finding a flaw in metal.

The study has given a new insight in how fertilisation occurs and will help reproductive biologists better understanding fertilisation process so that they can treat disabilities in a better war.

“This computational model revealed complementarity between the conserved SLLP1/SAS1B interacting surfaces supporting the experimentally observed SLLP1/SAS1B interaction involved in fertilisation,” the researchers said in their study.

The study was published in Andrology,

First published on Monday, August 31, 2015, 11:32 AM
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