The plasmodesmatal transport pathway for homeotic proteins, silencing signals and viruses.
Non-cell-autonomous signals in the form of microRNAs and transcription factors could have important developmental functions. Plasmodesmata (PD) form a cytoplasmic network throughout the plant body and provide the means of symplasmic cell-to-cell transport in plants. Homeodomain transcription factors, small RNA molecules and viral genomic information move selectively to adjacent cells via PD microchannels. Tissue-specific expression studies of non-cell-autonomous transcription factors and RNA molecules have confirmed that their intercellular transport is a highly regulated process, which depends on the tissue, developmental stage and nature of the transported macromolecule. We have known for some time that gene-silencing signals spread both locally from cell to cell and across long distances following the source to sink transition. Recent work has provided evidence that small single-stranded silencing-induced RNAs and microRNA molecules are present in the phloem transport system of different plant species. Further, recent evidence has confirmed that the transport of silencing RNA via PD is a regulated and active process, and that an amplification-relay mechanism is in place for the long-distance spread of silencing signals.
Ruiz-Medrano
Roberto
R
Department of Biotechnology and Bioengineering, CINVESTAV-IPN, Mexico DF 07360, Mexico.
Xoconostle-Cazares
Beatriz
B
Kragler
Friedrich
F
D000818:Animals; D001692:Biological Transport; D018398:Homeodomain Proteins / Q000378:metabolism*; D008954:Models, Biological; D010944:Plants / Q000378:metabolism*; D031425:Plasmodesmata / Q000378:metabolism*; D034622:RNA Interference; D018749:RNA, Plant / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D015398:Signal Transduction
D018398:Homeodomain Proteins; D018749:RNA, Plant; D016601:RNA-Binding Proteins