Editing Transcription factor (section)

==== Pathogenesis ====

Transcription factors can also be used to alter gene expression in a host cell to promote pathogenesis.  A well studied example of this are the transcription-activator like effectors ([[TAL effector]]s) secreted by [[Xanthomonas]] bacteria.  When injected into plants, these proteins can enter the nucleus of the plant cell, bind plant promoter sequences, and activate transcription of plant genes that aid in bacterial infection.<ref name="Boch J, Bonas U. 2010">{{Cite journal |vauthors=Boch J, Bonas U |year=2010 |title=Xanthomonas AvrBs3 family-type III effectors: discovery and function |journal=Annual Review of Phytopathology |volume=48 |issue=1 |pages=419–36 |doi=10.1146/annurev-phyto-080508-081936 |pmid=19400638|bibcode=2010AnRvP..48..419B }}</ref> TAL effectors contain a central repeat region in which there is a simple relationship between the identity of two critical residues in sequential repeats and sequential DNA bases in the TAL effector's target site.<ref name="Moscou2010">{{Cite journal |vauthors=Moscou MJ, Bogdanove AJ |date=December 2009 |title=A simple cipher governs DNA recognition by TAL effectors |journal=Science |volume=326 |issue=5959 |pages=1501 |bibcode=2009Sci...326.1501M |doi=10.1126/science.1178817 |pmid=19933106 |s2cid=6648530}}</ref><ref name="Boch J, Scholze H, Schornack S, ''et al.'' 2010">{{Cite journal |vauthors=Boch J, Scholze H, Schornack S, Landgraf A, Hahn S, Kay S, Lahaye T, Nickstadt A, Bonas U |date=December 2009 |title=Breaking the code of DNA binding specificity of TAL-type III effectors |journal=Science |volume=326 |issue=5959 |pages=1509–12 |bibcode=2009Sci...326.1509B |doi=10.1126/science.1178811 |pmid=19933107 |s2cid=206522347}}</ref> This property likely makes it easier for these proteins to evolve in order to better compete with the defense mechanisms of the host cell.<ref name="Voytas DF, Joung JK. 2010.">{{Cite journal |vauthors=Voytas DF, Joung JK |date=December 2009 |title=Plant science. DNA binding made easy |journal=Science |volume=326 |issue=5959 |pages=1491–2 |bibcode=2009Sci...326.1491V |doi=10.1126/science.1183604 |pmc=7814878 |pmid=20007890 |s2cid=33257689}}</ref>