Project description:Establishment and maintenance of epithelial architecture are essential for embryonic development and adult physiology. Here, we show that ERK3, a poorly characterized atypical MAPK, regulates epithelial architecture in vertebrates. In Xenopus embryonic epidermal epithelia, ERK3 knockdown impairs adherens and tight junction protein distribution, as well as tight junction barrier function, resulting in epidermal breakdown. Moreover, in human breast epithelial cancer cells, inhibition of ERK3 expression induces thickened epithelia with aberrant adherens and tight junctions. Microarray results suggest an involvement of TFAP2A, a transcription factor important for epithelial gene expression, in ERK3-dependent gene expression changes. TFAP2A knockdown phenocopies ERK3 knockdown in both Xenopus embryos and human cells, and ERK3 is required for full activation of TFAP2A-dependent transcription. Our findings thus reveal that ERK3 regulates epithelial architecture, possibly in cooperation with TFAP2A. We used microarrays to study the changes in ERK3-dependent gene expression profiles during pronephros and epidermal development in Xenopus laevis embryos.
Project description:Epithelia contribute to physical barriers that protect internal tissues from the external environment and also support organ structure. Accordingly, establishment and maintenance of epithelial architecture are essential for both embryonic development and adult physiology. Here, using gene knockout and knockdown techniques along with gene profiling, we show that extracellular signal-regulated kinase 3 (ERK3), a poorly characterized atypical mitogen-activated protein kinase (MAPK), regulates the epithelial architecture in vertebrates. We found that in Xenopus embryonic epidermal epithelia, ERK3 knockdown impairs adherens and tight-junction protein distribution, as well as tight-junction barrier function, resulting in epidermal breakdown. Moreover, in human epithelial breast cancer cells, inhibition of ERK3 expression induced thickened epithelia with aberrant adherens and tight junctions. Results from microarray analyses suggested that transcription factor AP-2α (TFAP2A), a transcriptional regulator important for epithelial gene expression, is involved in ERK3-dependent changes in gene expression. Of note, TFAP2A knockdown phenocopied ERK3 knockdown in both Xenopus embryos and human cells, and ERK3 was required for full activation of TFAP2A-dependent transcription. Our findings reveal that ERK3 regulates epithelial architecture, possibly together with TFAP2A.
Project description:Establishment and maintenance of epithelial architecture are essential for embryonic development and adult physiology. Here, we show that ERK3, a poorly characterized atypical MAPK, regulates epithelial architecture in vertebrates. In Xenopus embryonic epidermal epithelia, ERK3 knockdown impairs adherens and tight junction protein distribution, as well as tight junction barrier function, resulting in epidermal breakdown. Moreover, in human breast epithelial cancer cells, inhibition of ERK3 expression induces thickened epithelia with aberrant adherens and tight junctions. Microarray results suggest an involvement of TFAP2A, a transcription factor important for epithelial gene expression, in ERK3-dependent gene expression changes. TFAP2A knockdown phenocopies ERK3 knockdown in both Xenopus embryos and human cells, and ERK3 is required for full activation of TFAP2A-dependent transcription. Our findings thus reveal that ERK3 regulates epithelial architecture, possibly in cooperation with TFAP2A. We used microarrays to compare the changes in ERK3-dependent gene expression profiles with those in TFAP2A-dependent gene expression profiles in Xenopus laevis embryos.