Deciphering the molecular role of WOX5 bifunctional transcription in the columella stem cell niche of Arabidopsis thaliana

Abstract: In the center of the root system, the Quiescent Center (QC) comprises a unique population of stem cells known for their slow division rate and the capability to maintain the undifferentiated state of the surrounding cells. However, its precise genetic and epigenetic regulatory mechanisms remain largely unknown. By the comparison of the FANS-sorted QC population with the differentiated tissue of Columella Cells (CCs), my study revealed that the QC is preserved by enhancing the expression of genes related to meristem maintenance, control of gene expression, and nitrogen metabolism while downregulating differentiation and death processes. However, the QC might be primed for differentiation compared to CSC. Moreover, I found the active epigenetic marks H3K4me3 and H3K9ac related to the promotion of gene transcription in both the QC and CC. Despite sharing some common targets, both active marks also demonstrated specificity by engaging with unique biological processes.
It is known that the transcription factor WUSCHEL RELATED HOMEOBOX5 (WOX5) regulates QC specification, QC cell division, and in a non-cell-autonomous manner, the Columella Stem Cells (CSCs) pluripotency. Furthermore, ectopic expression of WOX5 can reverse differentiated columella cells into stem cells-like. How WOX5 controls these different processes is largely unknown. In this study, I profile a comprehensive genomic analysis of WOX5 function in the QC. My data show that WOX5 acts as a bifunctional transcriptional factor that modifies the epigenetic landscape of QC cells. WOX5 activates genes related to nitrate transport, response to osmotic stress, cell communication, and hormonal pathways, while simultaneously repressing ROS metabolism, response to oxidative stress and salicylic acid stimulus. I found that WOX5 is implicated in the modification of H3K4me3 and H3K9ac marks for gene activation and of H3K27m3 for gene repression. However, lacking the inherent capacity to catalyze the deposition or removal of these epigenetic marks, is presumed that WOX5 operates through the recruitment of epigenetic factors that subsequently affect chromatin compaction or relaxation to modulate gene expression. Furthermore, through a transcriptional factor (TF)-binding motif analysis, I found the enrichment of several TFs families such as WRKYs and TCPs within the WOX5 regulatory regions, suggesting a possible interaction among these TFs to regulate gene expression in the QC. Together, these results will increase our understanding of the molecular signatures that regulate the columella stem cell niche

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Universität Freiburg, Dissertation, 2023

Klassifikation und Themen

• Schlagwort: Genregulation ; Genexpression ; Stammzelle ; Ackerschmalwand

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2024
• Urheber: Aceves García, Pamela
• Beteiligte Personen und Organisationen: Laux, Thomas ; Hiltbrunner, Andreas ; Hartman, Sjon ; Albert-Ludwigs-Universität Freiburg. Fakultät für Biologie ; Albert-Ludwigs-Universität Freiburg. Fakultät für Biologie

Weitere Informationen

• DOI: 10.6094/UNIFR/242999
• URN: urn:nbn:de:bsz:25-freidok-2429996
• Rechteinformation: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 25.03.2025, 13:57 MEZ