Identification and Characterization of Mutants Related to LRS1 in Arabidopsis thaliana

Abstract

Lateral root stimulator 1 (LRS1) is a WD40-repeat protein that contains a Damaged DNA Binding (DWD) motif, suggesting an interaction with E3 ubiquitin ligases of the Damaged DNA Binding 1–Cullin 4 (DDB1-CUL4) type. Previous findings indicate LRS1 binds a deubiquitinase, indicating a role in ubiquitin regulation. Plant lines containing Agrobacterium T-DNA insertions in LRS1 have been identified for phenotypic analyses. Initial characterization of one lrs1 line (FS16) showed reduced roots, as previously described for the lrs1-1 allele. Altered leaf, flower, and seed morphologies, in addition to altered hormone responses, have also been observed. Comparison to wild-type sibling segregates (FS15), however, suggested the presence of additional mutations in the T-DNA line under study. To segregate the T-DNA insertion from unrelated mutations, FS16 plants are being back-crossed three times to wild-type Columbia (Col-0) and genotyped using PCR. In addition to these mutants, T-DNA lines mutated in genes encoding potential LRS1-interacting proteins, such as a RING (Really Interesting New Gene) E3 ubiquitin ligase and a histone methyltransferase, are also being analyzed. Characterization of mutant phenotypes will help elucidate the function of LRS1 in vivo and allow the exploration of its role in the regulation of ubiquitination. Funding has been provided by the Salisbury University Henson School of Science Undergraduate Research Grant.