# GENE EXPRESSION DURING LIMB CARTILAGE DIFFERENTIATION

> **NIH NIH R01** · UNIVERSITY OF CONNECTICUT SCH OF MED/DNT · 1994 · $131,763

## Abstract

The goal of this research is to understand the molecular regulation of
cartilage differentiation and cartilage-specific gene expression in the
developing chick limb bud.  A critical event in limb cartilage
differentiation is a transient cellular condensation process in which
prechondrogenic limb mesenchymal cells become closely juxtaposed, round-
up, and interact with one another prior to initiating cartilage-specific
gene expression.  A cDNA that encodes a membrane-intercalated
proteoglycan (PG) termed syndecan-3 that is expressed in high amounts
during this critical condensation process has been isolated.  Syndecan-3
contains a cytoplasmic domain potentially associated with the
cytoskeleton, and an ectodomain containing several putative GAG
attachment sites, as well as an extensive mucin-like domain potentially
containing numerous O-linked oligosaccharide chains.  The multiple
functional domains of syndecan-3 provide potential sites for mediating
the adhesive cell-matrix interactions and cytoskeletal reorganization
involved in the critical condensation phase of chondrogenesis.  Studies
will include a full characterization of the structure of syndecan-3, its
temporal and spatial pattern of expression during limb chondrogenesis,
and the possible regulation of its expression at the onset of
chondrogenesis by TGF-beta.  The role of syndecan-3 and other matrix
molecules in mediating precartilage condensation formation will be
studied.  It will be determined if phosphorylation of the cytoplasmic
domain of syndecan-3 and/or the shedding of its ectodomain from the cell
surface relate to the cytoskeletal reorganization and cell shape changes
that occur during condensation.  The binding of syndecan-3 to other
molecules expressed during condensation (PG-M, tenascin, cell surface
galactosyltransferases (GalTase) , fibronectin, type I collagen) and the
roles of PG-M, tenascin, and cell surface GalTase in condensation
formation will be studied.

## Key facts

- **NIH application ID:** 2198691
- **Project number:** 5R01HD022896-07
- **Recipient organization:** UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
- **SAM.gov UEI:** H6D6JMXJXDE6
- **Principal Investigator:** ROBERT A KOSHER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $131,763
- **Award type:** 5
- **Project period:** 1987-04-01 → 1998-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2198691

## Citation

> US National Institutes of Health, RePORTER application 2198691, GENE EXPRESSION DURING LIMB CARTILAGE DIFFERENTIATION (5R01HD022896-07). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2198691. Licensed CC0.

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