What is gene sharing?

[A. Hammouda]

What is gene sharing definition? and implications?

[Fazil Hussein]

Gene sharing is a term used in biology to describe a situation where a single gene codes for a protein that has multiple, distinct functions. This means that the same genetic instructions can be used to create a molecule that plays different roles in the cell or organism.

For example, the gene for the protein crystallin can be found in the eye lens, where it helps to refract light, and also in the liver, where it plays a role in detoxification.

Gene sharing is a common phenomenon in evolution, and it is thought to be an important way for organisms to create new functions from existing genes. When a gene is duplicated, one copy can continue to perform its original function, while the other copy is free to evolve new functions. This can lead to the development of new and complex traits.

[Y Soun]

The term ‘gene sharing’ means that a polypeptide generated from a specific region of a genome serves at least two distinct molecular functions. This novel concept originated about two decades ago from the work of Piatigorsky and his colleagues, who isolated genes that encode lens structural proteins, the crystallins. Studies of avian and crocodilian lenses first showed that ε-crystallin was similar to the basic metabolic enzyme, lactate dehydrogenase B4; followed by findings that chicken Δ-crystallin was similar to argininosuccinate lyase and that turtle τ-crystallin was similar to α-enolase. When gene identity for the enzyme and crystallin was revealed, both a novel term, ‘gene sharing’, and paradigm emerged.

[A. Hammouda]

Gene sharing and protein moonlighting are related concepts that describe multifunctional proteins:

1. Gene Sharing:
   • Definition: Gene sharing refers to a phenomenon where a single gene encodes a protein that performs more than one function.
   • Mechanism: Unlike alternative RNA splicing, DNA rearrangement, or post-translational processing (which generate different proteins from a single gene), gene sharing allows a single gene to maintain multiple distinct functions without duplicating itself.
   • Examples: Crystallins are well-studied examples of gene sharing. These proteins function as enzymes in various tissues but form densely packed lenses in the eye when expressed at high levels.
2. Protein Moonlighting:
   • Definition: Protein moonlighting refers to the ability of a single protein to perform multiple functions, often beyond its primary enzymatic role.
   • Evolution: Ancestral moonlighting proteins originally had a single function but acquired additional functions through evolution.
   • Functions: Moonlighting proteins can participate in signal transduction, transcriptional regulation, apoptosis, motility, and structural roles.
   • Difference: Unlike multifunctional proteins with distinct domains, moonlighting proteins maintain their primary function while gaining secondary non-enzymatic roles.
   • Detection: Unexpected protein locations within cells or sequence/structure homology can hint at moonlighting functions.

In summary, gene sharing involves a single gene encoding a multifunctional protein, while protein moonlighting describes a protein performing multiple roles beyond its primary enzymatic function.

 

Source: Microsoft Copilot

[Author]

Posts