Genetic diversity and population structure of Indian golden silkmoth (Antheraea assama).

Background: The Indian golden saturniid silkmoth (Antheraea assama), popularly known as muga silkmoth, is a semi-domesticated silk producing insect confined to a narrow habitat range of the northeastern region of India. Owing to the prevailing socio-political problems, the muga silkworm habitats in the northeastern region have not been accessible hampering the phylogeography studies of this rare silkmoth. Recently, we have been successful in our attempt to collect muga cocoon samples, although to a limited extent, from their natural habitats.

Successive phosphorylation of p27(KIP1) protein at serine-10 and C terminus crucially controls its potency to inactivate Cdk2.

During the G(1)-S transition, the activity of Cdk2 is regulated by its association with p27(KIP1), which in rodent fibroblasts undergoes phosphorylation mainly at serine 10, threonine 187, and C-terminal threonine 197 by KIS, Cdk2, and Pim or ROCK, respectively. Recently Cdc6 the AAA+ ATPase, identified initially to assemble pre-replicative complexes on origins of replication and later to activate p21(CIP1)-inactivated Cdk2, was found also to activate p27-bound Cdk2 but only after the bound p27 is C-terminally phosphorylated. On the other hand, the biological significance of the serine 10 phosphorylation remains elusive aside from its involvement in the stability of p27 itself.

Cdc6 protein activates p27KIP1-bound Cdk2 protein only after the bound p27 protein undergoes C-terminal phosphorylation.

In mammalian cells Cdk2 activity during the G(1)-S transition is mainly controlled by p27(KIP1). Although the amount and subcellular localization of p27 influence Cdk2 activity, how Cdk2 activity is regulated during this phase transition still remains virtually unknown. Here we report an entirely new mechanism for this regulation.