The red algal chloroplast genome encodes an essential prokaryotic cell division gene, ftsH, which has never been found in the mitochondrial genome of any organism. To compare the conserved prokaryote-derived mechanism for mitochondrial division with that of chloroplasts, we cloned chloroplast- and nuclear-encoded ftsH genes from the primitive red alga Cyanidioschyzon merolae. The deduced amino-acid sequence of chloroplast ftsH (ftsHcp) consists of 603 amino acids and shows the highest similarity with algal-chloroplast and cyanobacterial FtsH. On the other hand, the nuclear-encoded ftsH (ftsH2) encodes a protein of 920 amino acids and has the highest similarity with two yeast mitochondrial FtsHs, Rca1p and Afg3p. Furthermore, the amino-terminal extension of FtsH2 appears to be an amphipathic α-helix, a characteristic mitochondrial targeting signal, suggesting that FtsH2 is a mitochondrial protein. Southern hybridization revealed that ftsH2 is a single gene located on chromosome III of the 17 C. merolae chromosomes. The level of expression of the 3.0 and 4.0 kb transcripts of this gene decreased in concert during the organelle division phase of a synchronized culture, indicating a cell-cycle-dependent manner of ftsH2 transcription, while northern hybridization did not detect ftsHcp transcripts. Nevertheless, reverse transcription-PCR and immunoblotting demonstrated for the first time that chloroplast-encoded ftsH is transcriptionally and translationally active. Overproduction of FtsHcp and FtsH2 in Escherichia coli disrupted cytokinesis and produced filamentous cells, but had no effect on the replication, segregation, or distribution of their nucleoids, as also occurs in ftsH-deficient E. coli. These observations suggest the possible involvement of both C. merolae FtsHs in organelle division.
Plant Molecular Biology – Springer Journals
Published: Oct 16, 2004
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
All the latest content is available, no embargo periods.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud