Open AccessA plant cDNA that partially complements Escherichia coli recA mutations predicts a polypeptide not strongly homologous to RecA proteins.
Author(s) -
Qishen Pang,
John B. Hays,
Indira Rajagopal
Publication year - 1992
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.89.17.8073
Subject(s) - biology , escherichia coli , complementary dna , genetics , plasmid , mutant , dna , microbiology and biotechnology , homologous recombination , sos response , gene
A plant (Arabidopsis thaliana) cDNA previously selected for its ability to partially complement the UV sensitivity of Escherichia coli RecA-UvrC-Phr- mutants and designated DRT100 (DNA-damage repair/toleration) was subcloned into a high-copy-number plasmid and expressed via a bacterial promotor. It increased resistance of RecA-UvrB-Phr- bacteria to mitomycin C and methyl methanesulfonate as well as to UV light. This lack of specificity, and its ability to increase resistance in both UvrB- and UvrC- mutants, suggested that Drt100 activity might be complementing RecA- phenotypes. DRT100 partially complemented three RecA- phenotypes thought to reflect deficiencies in homologous recombination--namely, inability to plate lambda red-gam- phages and P1 phages and to recombinationally integrate donor DNA during conjugal crosses--but did not complement inability to induce E. coli SOS functions. The 395-amino acid DRT100 open reading frame encodes an apparent N-terminal chloroplast transit peptide and a putative 322-residue mature protein with a conserved nucleotide binding motif, but otherwise little global homology with bacterial RecA proteins. There are several tandemly repeated leucine-rich motifs. DNA from two closely related plants, but not from maize, hybridized strongly to a DRT100 cDNA probe.