NAC transcription factor: Difference between revisions

Additionally, the NAC domain also modulates protein binding that may determine fate and function of the NAC protein  <ref>http://www.ibt.unam.mx/computo/pdfs/ubiquita/sinat5.pdf</ref> <ref>http://www.biochemj.org/bj/371/0097/3710097.pdf</ref> <ref name="plantc">http://www.plantcell.org/content/22/4/1249.full.pdf+html</ref>[11-13]. Especially for VNDs, the VNI can directly interact with VND7, and as such, VND7 can directly interact with VND1-5  <ref name="plantc">http://www.plantcell.org/content/22/4/1249.full.pdf+html</ref>  <ref name="online">http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2011.04514.x/pdf</ref>[13,14]  Such contacts may also be crucial for plant–pathogen interaction or stress tolerance  <ref>http://www.springerlink.com/content/p82h815356615752/fulltext.pdf</ref> <ref>http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2006.02932.x/pdf</ref>[15,16]. The D subunit of some NAC domains contains a highly hydrophobic negative regulatory domain which acts to suppress transcriptional activity  <ref></ref> [17]. Many transcription factor family including Dof, WRKY, and APETALA, can be suppressed. Based on my alignment analyses, most of VNDs in Arabidopsis and poplar have this domain, but the function of this domain for VNDs remain elusive. The hydrophobicity associated with 'LVFY' residues or some structual interference with DNA-binding or nuclear transport in this region may be responsible for such repression. Thanks to the prescence of this domain, the positively charged Lys79, the exposed side chain of Arg85, and the hydrogen bond network of Arg 88 may mediate DNA binding activity  <ref>http://www.springerlink.com/content/x3t8826465j44p32/fulltext.pdf</ref> <ref>http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2011.04687.x/pdf</ref>[17,18]. Furthermore, recent protein structure analyses have shown that NAC domain can change in conformation when binds with DNA  <ref>http://www.biochemj.org/bj/imps/pdf/BJ20111742.pdf</ref>[19].

</ref>(1,33). The over-expression of VND6 and VND7 can induce ectopic differentiation of two different types of vessel elements: proto-xylem, and meta-xylem vessels. Reversely, the functional repression of VND6 and VND7 can inhibit vessel element formation. Additionally, the excellent works finished by Ye lab showed that the Arabidopsis VND6 and VND7 can complement the NST1NST3 double mutant phenotype, indicating that VNDs share the conserved functions with other secondary cell wall regulators  <ref name="plantbio"> http://www.plantbio.uga.edu/~zhye/2010-SWNTargets.pdf</ref>[34]. Then they found that the poplar VNDs can complement the Arabidopsis cell wall development defective mutant NST1NST3, suggesting that the conserved function of VNDs among different species  <ref></ref>[35]. Recently, the downstream genes of VND6 and VND7 were identified by the excellent works mainly done by Demura lab, Ye lab and Fukuda lab  <ref name="online">http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2011.04514.x/pdf</ref> <ref name="plantbio"> http://www.plantbio.uga.edu/~zhye/2010-SWNTargets.pdf</ref> <ref>http://www.plantcell.org/content/22/10/3461.full.pdf+html</ref>[14,34,36]. Both VND6 and VND7 regulates a battery of genes that are common with the downstream of SND1 (secondary cell wall related NAC domain transcription factor), a well known fiber developmental switch. The common downstream genes of VND6, VND7, and SND1 were MYBs transcription factor that have been identified as important regulators of secondary cell wall biosynthesis. However, VND6 and VND7 regulated LBD (Late organ boundery domain) transcription factor that involved in programmed cell death, indicating the important role of VND6 and VND7 in vessel development. The further elucidation of regulatory ways of VNDs not only promote our knowledge in vessel development, but also facilitate the engineering of plant stocks stem from cell wall suitable for biofuel production.