# STRUCTURAL BASIS OF C3 FUNCTIONS

> **NIH NIH R01** · SCRIPPS RESEARCH INSTITUTE, THE · 1990 · $270,221

## Abstract

The application's long-term objectives are to provide a
comprehensive understanding of the structure, biosynthesis and
regulation of expression for the third component of human
complement (C3).  Specific aims to be addressed during the proposed
funding period include (1) determination of the complete human C3
mRNA structure, (2) delineation of the structure of the human C3
gene, (3) assessment of differences in C3 tissue-specific
biosynthesis and the relationship to genomic transcriptional
control structures and (4) determination of the molecular basis for
human C3 deficiency.  Primer-extension studies utilizing human
liver mRNA as template will be employed to ascertain sequence for
the 5' end of C3 mRNA.  Sequence analysis of appropriate
restriction fragments derived from C3 cDNA isolated in this
laboratory will delineate structure for the 3' end of C3 mRNA.
Cloned genomic DNA spanning the 5' end of the C3 gene and beta-
chain coding region will be identified and isolated from cosmid
libraries using a restriction fragment from the 5' end of an
existing C3 cDNA as probe.  Sequence analysis by the Sanger dideoxy
procedure of pre-selected, exon-containing phage templates
subcloned from sheared DNA will allow a rapid determination of the
remaining exon/intron boundaries for the C3 gene.  The kinetics of
C3 synthesis by established cell lines and primary cell cultures
will be assessed by biosynthetic labeling studies.  These studies
will be extended to the RNA level.  The putative low molecular
weight Raja cell C3 transcript will be cloned and sequenced.  The
transcription start site(s) and the transcriptional control region
will be mapped employing cloned genomic DNA representative of the
5' end of the C3 gene.  Protein factors involved hepatic
transcription of the C3 gene will be identified and regions that
serve as protein binding sites mapped by performing DNA "footprint"
studies with nuclear protein extracts from hepatic (HepG2) and non-
hepatic cells.  The basis for C3 deficiency (C3D) in a well
characterized C3D kindred will be assessed by Southern analysis of
DNA prepared form EBV-transformed B cells of deficient and normal
individuals.  The C3 mRNA in deficient and normal family members
will be examined by Northern analysis and the defect at the protein
level assessed by sequences analysis of potential transcripts of
the defective gene.

## Key facts

- **NIH application ID:** 3128580
- **Project number:** 5R01AI019222-09
- **Recipient organization:** SCRIPPS RESEARCH INSTITUTE, THE
- **SAM.gov UEI:** PHZJFZ32NKH4
- **Principal Investigator:** BRIAN F TACK
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1990
- **Award amount:** $270,221
- **Award type:** 5
- **Project period:** 1981-12-01 → 1994-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3128580

## Citation

> US National Institutes of Health, RePORTER application 3128580, STRUCTURAL BASIS OF C3 FUNCTIONS (5R01AI019222-09). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3128580. Licensed CC0.

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