Dr. Man and her team, led by Professor David Kelsell, were studying the association between a mutation of a gene (GJB2) which produces a protein called Cx26 which is the most common cause of genetic deafness. Professor Kelsell was the first to describe the link between Cx26 mutations and deafness in 1997. "Since many people carry this mutation", Dr. Man said, "and people who have just one such mutation are not deaf, we felt that there might be some evolutionary advantage to it, so we decided to investigate how the mutation affected the ability of cells to communicate with each other in the epidermis where Cx26 is also expressed."
The cells within tissues such as skin need to be able to communicate with each other in order to retain their correct characteristics and allow the tissue to grow and repair itself. One way that cells communicate is through the regulated opening and closing of channels called gap junctions that link cells together. The main components of these channels are proteins called connexins, of which Cx26 is one.
"When we looked at the function of Cx26 in a laboratory skin model", said Dr. Man, "we found that it was directly associated with wound healing and bacterial invasion. We concluded that there is a definite advantage to carrying a mutation in this protein."
If a drug that temporarily knocks out Cx26 protein can be successfully delivered to the wound, healing could be improved. Such a drug could be useful in a wide range of epidermal wounds, she said. The scientists now intend to test the effect of Cx26 mutation in other epithelial cell types, such as the gut, where defence against infection is also important.
"It is interesting to speculate that Cx26 deafness mutations have been selected over the evolutionary process due to their beneficial effects on wound healing," said Dr. Man.