Knockdown of the intraflagellar transport protein IFT46 stimulates selective gene expression in mouse chondrocytes and affects early development in zebrafish.
Bone morphogenetic proteins (BMPs) act as multifunctional regulators in morphogenesis during development. In particular they play a determinant role in the formation of cartilage molds and their replacement by bone during endochondral ossification. In cell culture, BMP-2 favors chondrogenic expression and promotes hypertrophic maturation of chondrocytes. In mouse chondrocytes we have identified a BMP-2-sensitive gene encoding a protein of 301 amino acids. This protein, named mIFT46, is the mouse ortholog of recently identified Caenorhabditis elegans and Chlamydomonas reinhardtii intraflagellar transport (IFT) proteins. After generation of a polyclonal antibody against mIFT46, we showed for the first time that the endogenous protein is located in the primary cilium of chondrocytes. We also found that mIFT46 is preferentially expressed in early hypertrophic chondrocytes located in the growth plate. Additionally, mIFT46 knockdown by small interfering RNA oligonucleotides in cultured chondrocytes specifically stimulated the expression of several genes related to skeletogenesis. Furthermore, Northern blotting analysis indicated that mIFT46 is also expressed before chondrogenesis in embryonic mouse development, suggesting that the role of mIFT46 might not be restricted to cartilage. To explore the role of IFT46 during early development, we injected antisense morpholino oligonucleotides in Danio rerio embryos to reduce zebrafish IFT46 protein (zIFT46) synthesis. Dramatic defects in embryonic development such as a dorsalization and a tail duplication were observed. Thus our results taken together indicate that the ciliary protein IFT46 has a specific function in chondrocytes and is also essential for normal development of vertebrates.
Gouttenoire
Jérôme
J
Université de Lyon, Lyon, F-69003, Université Lyon 1, CNRS UMR5086, Institut de Biologie et Chimie des Protéines, IFR 128 BioSciences Gerland-Lyon Sud, 7 passage du Vercors, Lyon F-69367, France.
Valcourt
Ulrich
U
Bougault
Carole
C
Aubert-Foucher
Elisabeth
E
Arnaud
Estelle
E
Giraud
Lionel
L
Mallein-Gerin
Frédéric
F
D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002356:Cartilage / Q000196:embryology*; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism*; D020219:Chondrogenesis / Q000187:drug effects / Q000502:physiology*; D002923:Cilia / Q000235:genetics / Q000378:metabolism; D003598:Cytoskeletal Proteins; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology*; D006132:Growth Plate / Q000166:cytology / Q000196:embryology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology; D015800:Protozoan Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D029742:Caenorhabditis elegans Proteins; D003598:Cytoskeletal Proteins; C519209:IFT46 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D016376:Oligonucleotides, Antisense; D015800:Protozoan Proteins; D034741:RNA, Small Interfering; D016212:Transforming Growth Factor beta; D029961:Zebrafish Proteins