# MECHANISMS OF RNA TRANSPORT

> **NIH NIH R01** · PENNSYLVANIA STATE UNIV HERSHEY MED CTR · 1991 · $154,968

## Abstract

This proposal is designed to explore mechanisms operative in control of
nucleocytoplasmic RNA transport.  Its major thrusts encompass 1)
characterization of intron compartmentation in selection of RNA transcripts
for transport.  Metabolism of introns will be examined using cDNA
synthesized with specific polynucleotide promers and subsequently amplified
by the polymerase chain reaction.  Alterations in splice junctions will be
examined following A) treatment with chemical carcinogens, which alter
nucleocytoplasmic compartmentation and nuclear structure; and B) in
transfection experiments with a hamster cell line which produces functional
human immunodeficiency virus Rev protein, which modulates host cell
nucleocytoplasmic transport mechanisms via direct interaction with the
nuclear scaffold (NS) nucleoside triphosphatase (NTPase).  2) Definition of
the role of the 46kD NTPase in nucleocytoplasmic RNA transport.  This
enzyme is produced from lamins A/C, the major structural proteins of the
NS, by cleavage at a conserved tyrosine residue (aa376) near the end of
coil-2.  Substantial ATP-binding by cloned lamin C preparations has been
documented, which shows cooperative (K D =3x10-6 M) and non-cooperative (K
D =3x10-6 M) and non-cooperative (K D =2x10-5 M) sites which involve
histidine residues.  However, cloned lamin C preparations do not show
NTPase activity, suggesting that post-translational modifications or other
factors are important.  Therefore various expression systems and in vitro
modifications will be examined for relevance in production of active
NTPase.  Since NS NTPase activity and the 46 KD lamin fragment are
increased 300% following CCl 4 or thioacetamide treatment, without increase
in lamin mRNA, and since the 46 kD N-terminus lacks the nuclear
localization signal which dictates intranuclear import of lamins, we
hypothesize that newly discovered NS proteases are involved in post-
translational production of NTPase.  These proteases show a marked
selectivity for lamins A/C, are stringently regulated by Ca2+, and appear
to control NTPase production during mitotic regeneration and following
carcinogen treatment.  A number of monoclonal antibodies directed against
the 46 kDprotein have been developed.  These antibodies modulate NS NTPase
activity and have shown parallel modulation of RNA transport in vitro.
Anti-NTPase antibodies will be used in vitro, and inoocyte microinjection
studies to determine the role of the 46 kD NTPase in RNA transport, and the
properties of the NTPase will be directly explored.  Properties of the NS
proteases will be defined, and used to explore their role in production of
the NTPase from lamins A/C, using both cloned lamins and NS preparations.

## Key facts

- **NIH application ID:** 3179695
- **Project number:** 2R01CA040145-04A3
- **Recipient organization:** PENNSYLVANIA STATE UNIV HERSHEY MED CTR
- **SAM.gov UEI:** TNKGNDAWB445
- **Principal Investigator:** GARY A CLAWSON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1991
- **Award amount:** $154,968
- **Award type:** 2
- **Project period:** 1987-07-01 → 1996-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3179695

## Citation

> US National Institutes of Health, RePORTER application 3179695, MECHANISMS OF RNA TRANSPORT (2R01CA040145-04A3). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3179695. Licensed CC0.

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