TITLE:
Mutational Analyses of a Fork Head Associated Domain Protein, DAWDLE, in Arabidopsis thaliana
AUTHORS:
Lakshmi Ayiloor Narayanan, Dipaloke Mukherjee, Shuxin Zhang, Bin Yu, David Chevalier
KEYWORDS:
microRNA, DAWDLE, FHA Domain, Gene Mapping, Arabidopsis
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.18,
August
28,
2014
ABSTRACT: DAWDLE (DDL) gene encodes a protein that
contains an N-terminal arginine-rich domain and a C-terminal Fork Head
Associated (FHA) domain in Arabidopsis
thaliana. DDL protein is believed
to function in microRNA biogenesis by mediating the recruitment of pri-microRNA
to DICER-LIKE 1 and also stabilizing the microRNA. The aim of this study was to
conduct a structure-function analysis to identify the regions in DDL that are of functional significance.
Targeted Induced Local Lesions in Genome screen was performed in the Columbia erecta-105 background of Arabidopsis resulting in the
identification of eight point mutations spanning DDL. The mutants were characterized by phenotypic and molecular
analyses based on the prior knowledge on ddl knockout mutants. Height of the plant, hypocotyl and root length, and
fertility were measured for phenotypic characterization, and microRNA172 levels
were measured to assess the mutation effect at the molecular level. Phenotypic
and molecular analyses of the mutants revealed effects resulting in ddl phenotypes of varying degrees in
different organs and each mutant displayed at least one phenotype studied.
Reduction in fertility and increase in stem length were two phenotypes that
most of the mutants consistently displayed. Identification and characterization
of several key residues in the arginine rich region and FHA domain will serve
as an important tool for elucidation of DDL signaling pathway.