Ecdysone is a steroidal prohormone of the major insect molting hormone 20-hydroxyecdysone , which is secreted from the prothoracic glands . Insect molting hormones (ecdysone and its homologues) are generally called ecdysteroids . Ecdysteroids act as moulting hormones of arthropods but also occur in other related phyla where they can play different roles. In Drosophila melanogaster , an increase in ecdysone concentration induces the expression of genes coding for proteins that the larva requires, and it causes chromosome puffs (sites of high expression) to form in polytene chromosomes. Recent findings in Chris Q. Doe lab have found a novel role of this hormone in regulating temporal gene transitions within neural stem cells.  Ecdysone and other ecdysteroids also appear in many plants mostly as a protection agent (toxins or antifeedants) against herbivorous insects. These phytoecdysteroids have been reputed to have medicinal value and are part of herbal adaptogenic remedies like Cordyceps , yet an ecdysteroid precursor in plants has been shown to have cytotoxic properties.  A pesticide sold with the name MIMIC has ecdysteroid activity, although its chemical structure has little resemblance to the ecdysteroids.
More recently, an interaction between USP7 and the EBNA1 protein of Epstein-Barr virus (EBV) (another herpesvirus ) was also discovered.  This interaction is particularly interesting given the oncogenic potential (potential to cause cancer) of EBV, which is associated with several human cancers. EBNA1 can compete with p53 for binding USP7. Stabilization by USP7 is important for the tumor suppressor function of p53. In cells, EBNA1 can sequester USP7 from p53 and thus attenuate stabilization of p53, rendering the cells predisposed to turning cancerous. Compromising the function of p53 by sequestering USP7 is one way EBNA1 can contribute to the oncogenic potential of EBV. Additionally, human USP7 was also shown to form a complex with GMPS and this complex is recruited to EBV genome sequences.  USP7 was shown to be important for histone H2B deubiquitination in human cells and for deubiquitination of histone H2B incorporated in the EBV genome. Thus USP7 may also be important for regulation of viral gene expression.