CPEB nuclear localization domain. (A) Diagram of deletion mutant constructs of CPEB. PEST refers to a domain rich in proline, glutamic acid, serine, and threonine that is thought to be involved in protein destruction; RRM refers to RNA recognition motif, and ZF refers to zinc finger. (B) Immunocytochemistry of 3T3 cells expressing CPEB-HA full-length or deletions illustrated in panel A. (C) The nucleus-cytoplasm localization was quantified using an arbitrary score; this scoring system was used to analyze the relative localization of the CPEB proteins shown in panel B. Histograms of these data are presented in D; the numbers atop the bars refer to the total number of cells examined.
