DISSECTION OF HOOKLESS1 FUNCTION IN VIVO

Salk Institute For Biological Studies, La Jolla CA

Investigators

Abstract

HOOKLESS1 (HLS1) is an ethylene induced gene required for apical hook formation in Arabidopsis. It encodes a putative acetyltransferase, which has been shown to conjugate an acetyl group to a broad range of substrates, including small molecules such as spermadine and serotonin, the N-termini of proteins, and specific lysine side chains in histories. hlsl mutants completely lack an apical hook, but are otherwise wild type for ethylene-induced morphological changes, suggesting that it regulates differential cell growth and cell expansion in seedlings in response to the plant hormones ethylene and auxin. However, it is unclear how HLS 1 affects these processes at the molecular level. I propose to dissect the role of HLS 1 by determining its subcellular localization, targets and interacting factors. GFP and HLS 1 fusion genes will be expressed in plant cell to determine the subcellular localization of the protein. The yeast two-hybrid system and a biochemical chromatography method will be used to identify HLS1-interacting proteins. Suppressors of hls1 mutant, which restores the apical hook structure, will be screened. A screen using high density arrays of full length cDNA will be carried out to identify genes that require HLS1 for induction or repression. Finally, functions of HLS 1 homologs in plant growth and development will be investigated.