PLANT PHYSIOLOGY , Vol 102, Issue 1 155-163, Copyright © 1993 by American Society of Plant Biologists
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MOLECULAR BIOLOGY AND GENE REGULATION |
Treatment of Pea (Pisum sativum L.) Protoplasts with DNA-Damaging Agents Induces a 39-Kilodalton Chloroplast Protein Immunologically Related to Escherichia coli RecA
H. Cerutti, H. Z. Ibrahim and A. T. Jagendorf
Section of Plant Biology, Cornell University, Ithaca, New York 14853
Organisms must have efficient mechanisms of DNA repair and recombination to
prevent alterations in their genetic information due to DNA damage. There
is evidence for DNA repair and recombination in plastids of higher plants,
although very little is known at the biochemical level. Many chloroplast
proteins are of eubacterial ancestry, suggesting that the same could be
true for the components of a DNA repair and recombination system. A 39-kD
protein, immunologically related to Escherichia coli RecA, is present in
chloroplasts of pea (Pisum sativum L.). Bandshift gel assays suggest that
it binds single-stranded DNA. Its steady-state level is increased by
several DNA-damaging agents. These results are consistent with it being a
plastid homolog of E. coli RecA protein, presumably involved in DNA repair
and recombination, and with the existence of an SOS-like response in pea
leaf cells. Experiments with protein synthesis inhibitors suggest that the
39-kD chloroplast protein is encoded in the nucleus.
