Gene confers resistance to Marek’s disease
Scientists have identified a gene that appears to make chickens immune to the deadly Marek's virus - responsible for millions of deaths in chickens each year. The discovery could aid the breeding of birds that do not suffer from Marek's Disease.
Marek's disease virus (MDV) is a highly contagious virus similar to herpesvirus which has been linked to cervical cancer in women. MDV causes lymphomas - cancers of the immune system - which penetrate nerves and organs causing paralysis, organ failure and death. Whole flocks can be lost, costing the poultry industry more than ￡1.4 billion each year.
Some chickens are naturally immune to the disease and scientists wanted to know why. They studied the activity of genes in the thymus and spleens of both normal chickens and immune chickens that had been infected with the virus. This led to the identification of a gene encoding the HIC1 protein, which was found to be more active in resistant chickens.
They found that HIC1 controls cell death and switches on genes with anti-tumour protecting effects. The virus targets the same genes as the HIC1 protein but has the opposite effect by switching them off to cause cancer, and so higher levels of HIC1 defend the cell from the virus.
The gene is also found in humans and so the discovery could have important implications for human disease as well.