VESICULAR TRAFFIC IN THE SECRETORY PATHWAY: CLATHRIN-COATED VESICLE ASSEMBLY AS A FUNGICIDE TARGET
J KEON and J HARGREAVES
IACR-Long Ashton Research Station, Department of Agricultural Sciences, University of Bristol, Long Ashton, Bristol BS18 9AF, UK
Background and objectives
Results and conclusions
A U. maydis gamma-adaptin gene complements the or-ts mutant: a plasmid genomic library was transferred into the or-ts mutant and two plasmids containing overlapping DNA inserts were recovered from transformants that grew at the restrictive temperature. Analysis of the DNA sequence common to both inserts revealed a continuous open reading frame of 2652 bp encoding a protein containing 853 amino acids. Significant homology was found between the deduced amino acid sequence and the house mouse gamma-adaptin. Adaptors are known to consist of a central 'head' region flanked by two smaller appendages or 'ears', with each adaptin forming part of the 'head' with their N-terminal and an 'ear' with their C-terminal. Homology between the U. maydis gene product and the mouse gamma-adaptin was essentially restricted to the N-termini of the proteins.
Vesicle assembly as a fungicide target: the anilinopyrimidine fungicide, pyrimethanil, is known to act by interfering with the protein secretion pathway , thus demonstrating that vesicle transport from the TGN may be a potential target for new fungicide discovery. Furthermore, a fungal secondary metabolite, breveldin A, which also possesses antifungal activity, is known to prevent secretion of proteins by disrupting the structure and function of the Golgi complex. Indeed, an early event in the action of breveldin A is to prevent recruitment of gamma-adaptin and other vesicle coat proteins to the TGN .