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Analysis of BMP Heterodimer formation and function

BMP 异二聚体的形成和功能分析

基本信息

批准号：
10371195
负责人：
Jan L Christian
金额：
$ 19.06万
依托单位：
UNIVERSITY OF UTAH
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-04-01 至 2024-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10371195
关键词：
Alleles Amino Acid Substitution Amino Acids Anabolism Animal Model BMP2 gene BMP4 BMP5 gene BMP7 gene Biochemical Biological Assay Birth Bone Diseases Bone Injury Bone Morphogenetic Proteins Cleft Palate Complementary DNA Congenital Abnormality Data Defect Development Dimerization Disease Dysplasia Elements Embryo Embryonic Development Endoplasmic Reticulum Excision Exhibits Eye Eye Development Family Funding Future Gene Expression Goals Half-Life Heart Heterodimerization Heterozygote Homozygote Human Implant Individual Kidney Knock-in Knock-in Mouse Lead Ligands Light Mediating Molecular Conformation Morphogenesis Mus Mutation Organ Pathologic Pathway interactions Pattern Phenotype Phosphorylation Phosphotransferases Play Point Mutation Protein Precursors Publishing Raine syndrome Rana Recombinants Role Signaling Protein Testing Therapeutic Agents Trauma Wild Type Mouse Xenopus bone loss cardiogenesis cell fate specification dimer disulfide bond improved in vivo member mutant receptor regenerative agent therapeutically effective tumor

项目摘要

Bone morphogenetic proteins (BMPs) play critical roles in development, with members of the class I (BMP2 and 4) and class II (BMP5-7) BMP subfamilies being the dominant players. We have shown that class I/II heterodimers, rather than individual homodimers, generate most of the BMP activity that is required for early development. We generated knock-in mice carrying a mutation (Bmp7R-GFlag) that eliminates the function of all BMPs that heterodimerize with BMP7. Unlike Bmp7 null homozygotes, which die after birth, Bmp7R-GFlag homozygotes are embryonic lethal, have broadly reduced BMP activity and exhibit defects in multiple organs. Furthermore, compound heterozygotes carrying the Bmp7R-GFlag allele together with a null allele of Bmp2 or Bmp4 die during embryogenesis and show defects in ventral body wall closure, eye and heart development. Thus, BMP4/7 and BMP2/7 heterodimers play critical roles in early embryogenesis. This is important because class I/II heterodimers have significantly higher specific activity than either homodimer. The choice of whether a given BMP will form a homodimer or a heterodimer is made within the biosynthetic pathway. BMPs are made as inactive precursor proteins that are cleaved to generate the active, disulfide-bonded ligand along with two prodomain fragments. During biosynthesis the prodomain plays essential roles in guiding dimerization and folding of the ligand. We have previously shown that BMP4 preferentially forms heterodimers with BMP7 when co-expressed in Xenopus embryos, and that the prodomain of BMP4 is both necessary and sufficient for heterodimer formation. In new preliminary studies, we identified a key residue within the BMP4 prodomain that is required to generate fully functional homodimers and a second that is required for both homodimer and heterodimer function. Humans heterozygous for either mutation have congenital birth defects. In the current proposal, we will test the hypothesis that sequence elements within the BMP4 prodomain are required to generate functional BMP4 homodimers, and/or functional heterodimers with class II BMPs. We will: 1) Identify sequence elements in the BMP4 prodomain that are required for homodimer and/or heterodimer formation. We will generate cDNAs encoding BMP4 carrying amino acid substitutions within the prodomain that are associated with congenital defects in humans. Wild type or mutant BMP4 will be expressed alone or together with BMP7 in Xenopus embryos. Functional and biochemical assays will be used to compare the specific activity and folding of wild type and mutant BMP4 homodimers and heterodimers in vivo, and 2) Determine the role of BMP4 prodomain sequence elements in mammalian development. We will generate conditional knock-in mice carrying point mutations at the Bmp4 locus that lead to amino acid substitutions within the prodomain, and that are associated with congenital defects in humans We will perform preliminary analysis of development to collect data that will support future applications for funding for further analysis.

骨形态发生蛋白（BMPs）在发育过程中起着至关重要的作用，其中I类蛋白(BMP2和