The broad goal of this proposal is to understand the influence of matrix chondroitin sulfate proteoglycans (CSPGs) on IHH and FGF signaling in the developing limb growth plate. Heparan sulfate proteoglycans are known to be essential for normal trafficking of and signaling by morphogens such as IHH. However, only recently have genetic means allowed observation of the distribution, movement and signaling efficiency of morphogens in a CSPG-deficient matrix. Through study of naturally occurring mutants deficient in CSPGs, we have demonstrated that: i) CSPGs are critical to limb development from the initial formation of the growth plate onward;ii) signaling by IHH and FGF is dependent on the presence of sulfated CSPGs in the matrix;iii) the effect of CSPG composition on morphogen signaling changes over the course of development. Now that we have developed conditional knock-down and over-expression transgenic mice to modify matrix CSPG composition, we are in a unique position to be able to test additional hypotheses regarding morphogen-matrix interactions.
Two specific aims will be pursued: 1) Determine how PAPS synthetase isoforms affect proteoglycan sulfation and thereby influence signaling during postnatal growth plate development. 2) Elucidate the mechanism by which absence of CSPG core protein or CS chains affects IHH and FGF signaling throughout growth development.
Trafficking of and signaling by secreted morphogens is critically important for the normal development of numerous tissue and organ systems. The proposed studies will enhance a new field focused on the regulation of key factors by the extracellular matrix environment through which these factors must migrate to deliver signals to target cells. Analyses of the novel genetic models outlined in this proposal will provide valuable insights into how abnormal matrix components cause disruption of morphogen signaling, thus contributing to the pathogenesis of certain developmental disorders.
|Lauing, Kristen L; Cortes, Mauricio; Domowicz, Miriam S et al. (2014) Aggrecan is required for growth plate cytoarchitecture and differentiation. Dev Biol 396:224-36|
|Mis, Emily K; Liem Jr, Karel F; Kong, Yong et al. (2014) Forward genetics defines Xylt1 as a key, conserved regulator of early chondrocyte maturation and skeletal length. Dev Biol 385:67-82|
|Domowicz, Miriam S; Cortes, Mauricio; Henry, Judith G et al. (2009) Aggrecan modulation of growth plate morphogenesis. Dev Biol 329:242-57|
|Bradley, Michael E; Rest, Joshua S; Li, Wen-Hsiung et al. (2009) Sulfate activation enzymes: phylogeny and association with pyrophosphatase. J Mol Evol 68:1-13|
|Pirok 3rd, Edward W; Domowicz, Miriam S; Henry, Judith et al. (2005) APBP-1, a DNA/RNA-binding protein, interacts with the chick aggrecan regulatory region. J Biol Chem 280:35606-16|
|Singh, Bhawani; Schwartz, Nancy B (2003) Identification and functional characterization of the novel BM-motif in the murine phosphoadenosine phosphosulfate (PAPS) synthetase. J Biol Chem 278:71-5|
|Kurima, K; Singh, B; Schwartz, N B (1999) Genomic organization of the mouse and human genes encoding the ATP sulfurylase/adenosine 5'-phosphosulfate kinase isoform SK2. J Biol Chem 274:33306-12|
|Deyrup, A T; Krishnan, S; Singh, B et al. (1999) Activity and stability of recombinant bifunctional rearranged and monofunctional domains of ATP-sulfurylase and adenosine 5'-phosphosulfate kinase. J Biol Chem 274:10751-7|
|Deyrup, A T; Singh, B; Krishnan, S et al. (1999) Chemical modification and site-directed mutagenesis of conserved HXXH and PP-loop motif arginines and histidines in the murine bifunctional ATP sulfurylase/adenosine 5'-phosphosulfate kinase. J Biol Chem 274:28929-36|
|Deyrup, A T; Krishnan, S; Cockburn, B N et al. (1998) Deletion and site-directed mutagenesis of the ATP-binding motif (P-loop) in the bifunctional murine ATP-sulfurylase/adenosine 5'-phosphosulfate kinase enzyme. J Biol Chem 273:9450-6|
Showing the most recent 10 out of 41 publications