InterPro domain: IPR016262

This entry represents certain plastid RNA polymerase sigma factors, including SigB, SigC, SigD and sigF [ 1 , 2 ]. Development of plastids into chloroplasts is triggered by light. The coordination of light-induced plastid gene expression is directed by both nuclear and plastid genomes. Plastid DNA is transcribed by at least two types of RNA polymerase, plastid-encoded RNA polymerase (PEP) and nuclear-encoded RNA polymerase (NEP). Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. Sigma factor SigB appears to play a critical role in the coordination of the two genomes for chloroplast development [ 3 ].

1. Plastidic RNA polymerase sigma factors in Arabidopsis. Plant Cell Physiol. 40, 832-42
2. Three new nuclear genes, sigD, sigE and sigF, encoding putative plastid RNA polymerase sigma factors in Aarabidopsis thaliana. FEBS Lett. 481, 47-52
3. Chloroplast development in Arabidopsis thaliana requires the nuclear-encoded transcription factor sigma B. FEBS Lett. 485, 178-82