The discovery of plastid-to-nucleus retrograde signaling-a personal perspective.
DNA and machinery for gene expression have been discovered in chloroplasts during the 1960s. It was soon evident that the chloroplast genome is relatively small, that most genes for chloroplast-localized proteins reside in the nucleus and that chloroplast membranes, ribosomes, and protein complexes are composed of proteins encoded in both the chloroplast and the nuclear genome. This situation has made the existence of mechanisms highly probable that coordinate the gene expression in plastids and nucleus. In the 1970s, the first evidence for plastid signals controlling nuclear gene expression was provided by studies on plastid ribosome deficient mutants with reduced amounts and/or activities of nuclear-encoded chloroplast proteins including the small subunit of Rubisco, ferredoxin NADP+ reductase, and enzymes of the Calvin cycle. This review describes first models of plastid-to-nucleus signaling and their discovery. Today, many plastid signals are known. They do not only balance gene expression in chloroplasts and nucleus during developmental processes but are also generated in response to environmental changes sensed by the organelles.
Institute of Biology, Molecular Genetics, Humboldt University Berlin, Rhoda Erdmann Haus, Philippstr 13, 10115, Berlin, Germany. thomas.boerner@rz.hu-berlin.de.
Thomas
http://orcid.org/0000-0001-9548-3348
T
Börner
D002467:Cell Nucleus / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018087:Plastids / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
Chloroplast development; Chloroplast signal; Plastid signal; Regulation of gene expression; Retrograde signaling