PRT1 of Arabidopsis thaliana encodes a component of the plant N-end rule pathway

PRT1 of Arabidopsis thaliana encodes a component of the plant N-end rule pathway

Institute of Botany, University of Vienna, Rennweg 14, A-1030 Vienna, Austria

Communicated by Alexander Varshavsky, California Institute of Technology, Pasadena, CA (received for review April 2, 1998)

Abstract

Mutants in the PRT1 gene of Arabidopsis thaliana are impaired in the degradation of a normally short-lived intracellular protein that contains a destabilizing N-terminal residue. Proteins bearing such residues are the substrates of an ubiquitin-dependent proteolytic system called the N-end rule pathway. The chromosomal position of PRT1 was determined, and the PRT1 gene was isolated by map-based cloning. The 45-kDa PRT1 protein contains two RING finger domains and one ZZ domain. No other proteins in databases match these characteristics of PRT1. There is, however, a weak similarity to Rad18p of Saccharomyces cerevisiae. The RING finger domains have been found in a number of other proteins that are involved in ubiquitin conjugation, consistent with the proposed role of PRT1 in the plant N-end rule pathway.

Footnotes

↵ * Present address: GPC AG Genome Pharmaceuticals Corporation, Lochhamer Str. 29, D-82152 Martinsried Germany.
↵ † To whom reprint requests should be addressed. e-mail: bachmair{at}s1.botanik.univie.ac.at.
Data deposition: The sequences reported in this paper have been deposited in the GenBank database (accession nos. AJ224306 and AJ224307).
ABBREVIATIONS:

DHFR,

dihydrofolate reductase;

F-DHFR,

DHFR with an extension bearing an N-terminal phenylalanine residue;

MTX,

methotrexate;

YAC,

yeast artificial chromosome