Kafatos F C, Feder N
Science. 1968 Aug 2;161(3840):470-2. doi: 10.1126/science.161.3840.470.
In the galea of silkmoths undergoing metamorphosis, generalized epidermal cells, which had previousty secreted pupal cuticle, transform into highly specialized cells producing a new protein, the enzyme cocoonase. These cells first segregate by mitosis and displacement, then grow rapidly through endomitosis and accumulation of RNA-rich cytoplasm, and finally begin rapid synthesis of cocoonase. Replication of DNA continues in fully differentiated cells synthesizing cocoonase.