STAT3 Expression And Activation During Mouse Embryonic And Early Postnatal Development

Signal transducer and activator of transcription 3 (STAT3) has been considered one of the most important transcription factors which has been link to many cell processes, including cell growth, proliferation etc.. STAT3 plays important roles in tumorigenesis by activating numerous oncogenes in response to cytokines like IL-6, LIF, EGF, PDGF, OSM. Meanwhile, STAT3 is essential for mouse development especially in embryonic stages, STAT3 deficient mice died around E7.5. Conditional knockout or mutant forms of STAT3 might lead to some abnormal physiological phenotypes and even serious diseases. However, it's still unclear how STAT3 functions in mouse embryonic development and why STAT3-knockout could cause lethal effects through previous researches. Here, we investigated STAT3 expression and activation during mouse embryonic and early postnatal development. STAT3 is present in postimplantation decidual around E8.5 and embryos from E9.5 through E18.5 and several days postnatal. Phosphorylation of STAT3, however, was only dominantly detected in decidual swellings and around later embryonic development stages. STAT3 positive cells in liver decreased from E10.5 to E15.5, indicating a potential model might be involved in hematopoietic cell migration. Significant activation at 1 dpp indicated that STAT3 might be essential for the newborn postnatal mice. No activity of its related protein, STAT1, was detected during embryonic development, suggested that embryonic development may not require STAT1 activity.