|Home | About | Journals | Submit | Contact Us | Français|
Memory is a crucial adaptation modulating responses to environmental stimuli. Although epigenetic control of active transcription is well understood, little is known about molecular mechanisms of transcriptional memory. Gialitakis et al. (p. 2046-2056) describe the generation of memory by interferon-induced transcription of major histocompatibility complex class II genes. They explain how this is brought about by locus relocalization in the proximity of PML bodies. This results in persistence of epigenetic marks that are perpetuated through subsequent cell generations to allow a more rapid and effective response upon successive stimulation.
In the classical model of progesterone action, progesterone receptor (PR) interacts with specific response elements within target gene promoters to elicit transcription. Wade et al. (p. 1866-1877) show that while E2F1 transcription is impacted by direct interaction of PR with regulatory regions near E2F1, maximal induction of E2F1 expression by progestins requires additional indirect PR actions, including hyperphosphorylation of Rb and induction of KLF15 expression. Their results suggest a global paradigm for multimodal PR gene regulation that entails cooperation between direct and indirect pathways of PR signaling to achieve the desired downstream transcriptional cascade.