title: Regulation of Ripply1 expression in MDCK organoids.
abstract: Epithelial organs are made of a well-polarized monolayer of epithelial cells, and their morphology must be maintained for their proper function. To examine the genes that are specifically expressed in the late stages of cystogenesis and are involved in maintaining the morphology of the mature cysts, we performed a microarray analysis comparing the mRNA expression between the early and late stages of Madin-Darby Canine Kidney (MDCK) cystogenesis. We found that one of the gene candidates, Ripply1, was expressed higher in the late stages, and its expression was also transiently much higher in the early stages. Although the protein expression showed similar kinetics, depletion of Ripply1 had only a slight effect on organoid growth. Unexpectedly, we found that the Ripply1 protein is degraded by the proteasome system. Mutant analysis suggests that Ripply1 is not ubiquitinated directly, but rather is degraded only after binding to Transducin-like Enhancer of Split (TLE)1, a transcriptional repressor. Ripply1 is degraded in the nucleus, and this degradation is inhibited during the mitosis. These data indicate for the first time that Ripply1 expression is regulated at the protein level.
authors.affiliation: Department of Oncologic Pathology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku-gun, Ishikawa 920-0293, Japan; Department of Pediatric Surgery, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku-gun, Ishikawa 920-0293, Japan.
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Yoshizaki
authors.affiliation: Department of Oncologic Pathology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku-gun, Ishikawa 920-0293, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kuwajima
authors.affiliation: Department of Pathology and Laboratory Medicine, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku-gun, Ishikawa 920-0293, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Minato
authors.affiliation: Department of Oncologic Pathology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku-gun, Ishikawa 920-0293, Japan. Electronic address: kiyokawa@kanazawa-med.ac.jp.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Kiyokawa
mesh_terms: D000818:Animals; D004285:Dogs; D005786:Gene Expression Regulation; D061985:Madin Darby Canine Kidney Cells / Q000166:cytology* / Q000378:metabolism; D008938:Mitosis; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D009940:Organoids / Q000166:cytology* / Q000378:metabolism; D059748:Proteolysis; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D012097:Repressor Proteins
keywords: Cell division; MDCK; Organoid; Protein degradation