# STRUCTURAL & CHEMICAL STUDY OF TISSUE CALCIFICATION

> **NIH NIH R01** · UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON · 1993 · $106,040

## Abstract

The overall goal of this project is to identify and characterize
intermediate calcium carriers which have a common mineralizing function in
distantly related organism and to determine how carrier-bound calcium ions
are utilized to form a crystalline mineral phase.  As a working hypothesis,
it is proposed that polyanionic macromolecules function as intermediate
calcium carriers, i.e. that polyanions are charged with mineral ions
intracellularly and are subsequently degraded at calcifying foci releasing
mineral ions for crystal growth.  The specific aims are designed to test
the carrier hypothesis in two homogeneous cell populations and in a complex
metazoan tissue.

The first aim is to identify and characterize the calcium-binding
polyuronides that are apparently degraded at the mineralization front in
coccolithophorid algae.  The kinetics of polyuronide turnover will be
analyzed to determine if there is a one-to-one correspondence between the
number of calcium ions released via the degradation of these polyanions and
the number of calcium ions deposited in the mineral phase.  The second aim
is to determine whether the spicule-forming primary mesenchyme cells
derived from sea urchin embryos express a polyanionic calcium-binding
phosphoprotein(s).  If a protein with these properties is expressed, its
calcium-binding capacity and rate of turnover will be analyzed in relation
to the rate of calcium deposition in the spicules.  The third aim is to
examine the self-association of a bone phosphoprotein osteopontin in the
presence of calcium, magnesium and phosphate ions.  The purpose of this
study is to determine whether osteopontin forms discrete aggregates
containing sequestered Ca3 (PO4)2-like complexes similar to known calcium-
carriers, e.g. casein.  The fourth aim is to examine the distribution of
phosphoproteins in the matrix of embryonic chick calvaria to determine
whether matrix phosphoprotein is preferentially concentrated at
mineralizing foci.

This project is relevant to normal skeletal and pathological calcification
processes.

## Key facts

- **NIH application ID:** 3157502
- **Project number:** 5R01AR036239-10
- **Recipient organization:** UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
- **SAM.gov UEI:** ZUFBNVZ587D4
- **Principal Investigator:** MARY E MARSH
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $106,040
- **Award type:** 5
- **Project period:** 1985-01-01 → 1995-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3157502

## Citation

> US National Institutes of Health, RePORTER application 3157502, STRUCTURAL & CHEMICAL STUDY OF TISSUE CALCIFICATION (5R01AR036239-10). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3157502. Licensed CC0.

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