ABSTRACT
Bone morphogenetic protein 1 (BMP1) is a metalloprotease that ventralises dorsal mesoderm when overexpressed in early Xenopus embryos. Here we show that Xenopus BMP1 blocks the dorsalising activity of chordin, but not noggin or DeltaxBMPR, when coexpressed in the ventral marginal zone and degrades chordin protein in vitro. We also show that a dominant-negative mutation for XBMP1 (dnBMP1) dorsalises ventral mesoderm in vivo, and blocks degradation of chordin by both XBMP1 and Xolloid, a closely related Xenopus metalloprotease, in vitro. dnBMP1 does not dorsalise ventral mesoderm in UV-irradiated embryos, demonstrating that this activity is dependent upon a functional organiser--the natural source of chordin in Xenopus gastrulae. Our results suggest that XBMP1 may regulate the availability of chordin during vertebrate embryogenesis.
Subject(s)
Bone Morphogenetic Proteins/metabolism , Glycoproteins , Intercellular Signaling Peptides and Proteins , Metalloendopeptidases/metabolism , Proteins/metabolism , Xenopus Proteins , Xenopus laevis/embryology , Animals , Body Patterning/physiology , Bone Morphogenetic Protein 1 , Bone Morphogenetic Protein 4 , Carrier Proteins , Ectoderm/radiation effects , Embryo, Nonmammalian/metabolism , Embryo, Nonmammalian/radiation effects , Gene Expression Regulation, Developmental , Genes, Dominant , Mesoderm/radiation effects , Metalloendopeptidases/genetics , Mutation , Proteins/genetics , Ultraviolet RaysABSTRACT
This paper presents a brief review of the basic issues of lyophilization and the fundamentals of quadrupole mass spectrometry. The emphasis of the paper is on the application of a quadrupole mass spectrometer as a process monitor. The details of sampling and data collection are discussed. Data taken while monitoring lyophilization is presented in conjunction with cycle optimization, end point detection and contaminant detection.