DUALITY AND DEVELOPMENTAL-CHANGES OF CHICKEN THYMUS - DNA LIGASES

Chick embryo DNA ligases occur in two forms in the thymus. The first form is a heavy molecule with a molecular weight of 165 000; the second has a molecular weight of 82 000. Developmental studies of the sucrose gradient and phosphocellulose extract of thymus show that the heavy enzyme persists until the day of hatching and the light molecular weight enzyme appears at birth. The possible involvement of these forms in differentiation and repair is discussed. Also discussed is the significance of this change with regard to the hormonal development of the chicken embryo and of the chicken. © 1979.