# REGULATION OF TRYPANOSOME DNA REPLICATION

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 1992 · $295,337

## Abstract

The kinetoplastid flagellates represent a unique opportunity for
investigating eukaryotic DNA replication mechanisms and their coordination
with the cell cycle. These parasitic protozoa are distinguished by the
presence of a single mitochondrion which contains approximately 5,000
copies of a plasmid-like DNA (minicircles) catenated into an enormous
network together with 25-50 copies of the mitochondrial DNA (maxicircles).
The kinetoplast DNA (kDNA) accounts for approximately 25% of the cellular
DNA and, unlike mammalian mitochndrial DNA, replicates coordinately with
the nuclear S phase.  The long-term goal of this proposal is to determine
the biochemical and enzymatic mechanisms os replication of the kDNA
minicircles in the trypanosomatid Crithidia fasciculata and to identify
features of the mechanism coordinating minicircle replication with the cell
cycle.  Kinetoplast-associated proteins involved in initiation and possible
pre-initiation steps in minicircle replication will be purified and used to
supplement crude kinetoplast extracts in order to develop a minicircle-
dependent DNA replication system.  The enzymes involved in RNA-primed
initiation at minicircle replication origins will be purified and used to
determine the mechanism and the sites of initiation.  Antibodies against
purified replication proteins will be used to localize individual proteins
within the kinetoplast and to determine the possible association of
additional replication proteins with the two topoisomerase-containing
structures located, in previous studies, at the periphery of the kDNA
network.  The gene encoding the kinetoplast-associated topoisomerase will
be cloned and sequenced and the expression of RNA and protein products of
the gene will be determined at various times in the cell cycle.  Protein-
protein interactions of the topoisomerase will be sought and, if found,
exploited to identify and purify possible associated proteins of the
replication apparatus.

This proposal addresses fundamental questions in modern cell biology and
therefore is relevant to an understanding of both normal and abnormal
growth and development  of cells and tissues.  In addition, unique features
of the kinetoplast DNA replication mechanism may reveal appropriate targets
for the development of new chemotherapeutic drugs for the treatment of
trypanosomiasis and leishmaniasis.

## Key facts

- **NIH application ID:** 3129609
- **Project number:** 5R01AI020080-10
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **SAM.gov UEI:** RN64EPNH8JC6
- **Principal Investigator:** DAN S RAY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1992
- **Award amount:** $295,337
- **Award type:** 5
- **Project period:** 1983-07-01 → 1994-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3129609

## Citation

> US National Institutes of Health, RePORTER application 3129609, REGULATION OF TRYPANOSOME DNA REPLICATION (5R01AI020080-10). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3129609. Licensed CC0.

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