title: Pregnancy-associated plasma protein A (PAPP-A) modulates the early developmental rate in zebrafish independently of its proteolytic activity.
abstract: Pregnancy-associated plasma protein-A (PAPP-A) is a large metalloproteinase specifically cleaving insulin-like growth factor (IGF) binding proteins, causing increased IGF bioavailability and, hence, local regulation of IGF receptor activation. We have identified two highly conserved zebrafish homologs of the human PAPP-A gene. Expression of zebrafish Papp-a, one of the two paralogs, begins during gastrulation and persists throughout the first week of development, and analyses demonstrate highly conserved patterns of expression between adult zebrafish, humans, and mice. We show that the specific knockdown of zebrafish papp-a limits the developmental rate beginning during gastrulation without affecting the normal patterning of the embryo. This phenotype is different from those resulting from deficiency of Igf receptor or ligand in zebrafish, suggesting a function of Papp-a outside of the Igf system. Biochemical analysis of recombinant zebrafish Papp-a demonstrates conservation of proteolytic activity, specificity, and the intrinsic regulatory mechanism. However, in vitro transcribed mRNA, which encodes a proteolytically inactive Papp-a mutant, recues the papp-a knockdown phenotype as efficiently as wild-type Papp-a. Thus, the developmental phenotype of papp-a knockdown is not a consequence of lacking Papp-a proteolytic activity. We conclude that Papp-a possesses biological functions independent of its proteolytic activity. Our data represent the first evidence for a non-proteolytic function of PAPP-A.
authors: Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark.
authors: Kasper
authors: K
authors: Kjaer-Sorensen
authors: Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark.
authors: Ditte H
authors: DH
authors: Engholm
authors: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48105.
authors: Hiroyasu
authors: H
authors: Kamei
authors: Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark.
authors: Maria G
authors: MG
authors: Morch
authors: Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark.
authors: Anisette O
authors: AO
authors: Kristensen
authors: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48105.
authors: Jianfeng
authors: J
authors: Zhou
authors: Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905.
authors: Cheryl A
authors: CA
authors: Conover
authors: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48105.
authors: Cunming
authors: C
authors: Duan
authors: Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark. Electronic address: co@mb.au.dk.
authors: Claus
authors: C
authors: Oxvig
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D018507:Gene Expression Regulation, Developmental; D016678:Genome; D057809:HEK293 Cells; D006801:Humans; D017403:In Situ Hybridization; D045726:Metalloproteases / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry; D013002:Somatomedins / Q000378:metabolism; D015027:Zebrafish
chemical_list: D011994:Recombinant Proteins; D013002:Somatomedins; D045726:Metalloproteases; D011266:Pregnancy-Associated Plasma Protein-A