Treatment of Pea (Pisum sativum L.) Protoplasts with DNA-Damaging Agents Induces a 39-Kilodalton Chloroplast Protein Immunologically Related to Escherichia coli RecA

Abstract

The DNA of a cell undergoes significant damage solely as a result of thermal fluctuations and normal metabolic activity (Lindahl and Nyberg, 1972; McLennan, 1988;Richter et al., 1988). Moreover, many chemical or physical agents can cause DNA damage (Saffhill et al., 1985; McLennan, 1988). To maintain accurately their genetic information, plants must have efficient mechanisms of DNA repair presumably operating in each of the different DNA-containing organelles. Eubacteria, yeast, and mammalian cells possess several pathways of DNA repair, namely, direct repair (like photoreacti-'

The Role of Heterologous Chloroplast Sequence Elements in Transgene Integration and Expression

“…The most important factor for homologous recombination is the extent and degree of sequence similarity between the recombining fragments and is mediated by recombination/repair en- zymes. The RecA protein is mainly responsible for facilitating recombination, and its homolog has been identified in land plant plastids (Cerutti et al, 1992(Cerutti et al, , 1993Inouye et al, 2008). Studies demonstrate a loglinear relationship between recombination rate and the degree of sequence divergence, independent of the activity of the mismatch repair system (Shen and Huang, 1986;Majewski and Cohan, 1998).…”

Expression and Complementation Analyses of a Chloroplast-Localized Homolog of Bacterial RecA in the MossPhyscomitrella patens

“…13) In pea chloroplasts, strand transfer activity resembling that of bacterial RecA was detected 14) and a protein cross-reacting with the Escherichia coli RecA antibody was identified. 15) A RecA dependent recombination system has also been suggested for the chloroplast of Chlamydomonas reinhardtii, unicellular green algae, 16) and the C. reinhardtii chloroplast RecA was identified. 17) Thus it is likely that an RecA-dependent recombination and repair system is ubiquitous and well conserved among chloroplast genetic systems, but little is known about the biological significance of homologous recombination in chloroplasts.…”

Identification and Expression Analysis of cDNA Encoding a Chloroplast Recombination Protein REC1, the Chloroplast RecA Homologue inChlamydomonas reinhardtii

“…As for the chloroplast RecA, a 39-kDa protein immunologically related to the E. coli RecA protein was found to be induced by DNA-damaging reagents such as methylmethane sulfonate (MMS), mitomycin C, and nalidixic acid in pea chloroplasts. 8) Induction of mRNA by MMS was also found for the chloroplast-located RecA homolog in Arabidopsis. 10) However, no information is thus far available for the regulatory circuits.…”

“…Induction by DNA damages was also suggested for a chloroplast RecA protein in a higher plant. 8) To analyze the control of the REC1 gene expression in Chlamydomonas, we added DNA damaging reagents to the culture, and the REC1 expressions were monitored by the Northern hybridization analysis. Bleomycin and MMS are widely used DNA-damaging drugs.…”

“…In pea chloroplasts, a strand recombination activity resembling that of bacterial RecA was detected, and a protein cross-reacted with the Escherichia coli RecA antibody was identiˆed. 8) And subsequently, an Arabidopsis cDNA encoding for a RecA homologue for chloroplasts was isolated and analyzed. 9,10) A RecA-dependent recombination system was also suggested for the chloroplast of Chlamydomonas reinhardtii, a unicellular green alga.…”