자료유형  

 학위논문

Control Number  

0017162191

International Standard Book Number  

9798384217725

Dewey Decimal Classification Number  

574

Main Entry-Personal Name  

Spencer, Dirk Junior Jamal.

Publication, Distribution, etc. (Imprint  

[S.l.] : Stanford University., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

89 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-03, Section: A.

General Note  

Advisor: Bergmann, Dominique;Feldman, Jessica;Shapiro, Lucy.

Dissertation Note  

Thesis (Ph.D.)--Stanford University, 2024.

Summary, Etc.  

요약With multicellularity has come additional capacity for cells to become functionally and structurally diverse; along with diversity comes a need for organization and patterning. The formation of distinct cell types is often linked to asymmetric cell divisions (ACDs) in which a cell divides to create daughters that differ in size, composition, proximity to signaling sources, and ultimately fate. Cortical cell polarity is an important feature of ACDs. In animal cells, the PAR proteins play an important role in establishing cortical polarity driving ACDs and axis formation, but they are conspicuously absent from plant genomes. Interestingly, we see the conservation of mechanistic logic cells used to build polarity complexes. For example, AGC kinases enforce or reinforce cell polarity in plants, animals, and fungi.The stomatal lineage of Arabidopsis thaliana presents us with a unique opportunity to understand how cell polarity and orchestrated cell divisions contribute to a robust developmental plan. Core to this process are the cortically polarized scaffolding proteins BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL) and the BREVIS RADIX family (BRXf). These novel, plant-specific proteins are required to ensure proper asymmetric divisions in stomatal lineage cells. Loss of BASL results in more symmetric divisions and an over-proliferation of epidermal cells of mixed identity. To further elucidate BASL/BRXf's ability to confer ACD competency to stomatal lineage cells, we, in collaboration with proteomics specialist Geert De Jager (VIB Belgium), did a protein interaction screen that yielded several interaction partners for BRXL2. Among the candidates identified in the assay were members of the plant-specific PIN-FORMED (PINs) family and members of the AGCVIII kinase family.In this thesis, I present genetic and cell biological data that support a novel role for the AGCVIII kinase D6PK in facilitating asymmetric cell division and asymmetric fate acquisition in the stomatal lineages through the BASL and BRXL2. D6PK is broadly expressed in the leaf and is present in stomatal lineage cells, mature pavement cells, and guard cells. Furthermore, D6PK is localized to the BASL/BRXf polarity complex in the stomatal lineage. Its polarization mirrors BASL and BRX proteins during asymmetric cell division in that the D6PK polar crescent is inherited by the larger daughter cell. Further, we show that D6PK is required for patterning stomata. Stomatal lineage cells in the d6pk012 triple mutant background divided excessively and occasionally acquired identical fates, resulting in paired guard cells. Known transcriptional regulators are also disrupted in d6pk012. Due to the nature of the phenotype, we speculated that D6PK might be a core member of the BASL/BRXf polarity complex or a regulator of polarity. D6PK and BASL polarity are mutually dependent, while D6PK maintained some ability to polarize in the brxqbackground.Interestingly, D6PK polarity did not require BASL in mature pavement cells and mid-vein cells. D6PK may regulate stomatal patterning through a PIN-independent mechanism that requires the phosphorylation of BASL but not BRXL2. In comparing root and shoot systems, we draw two conclusions: (1) the stomatal lineage polarity system diverges in function from the polarity system found in root vascular cells, and (2) D6PK may function similarly to AGC kinases in animal polarity systems. The appendix of this thesis explores D6PKs' relationship with cell signaling factors, additional interactors of BRXL2, and automated cell segmentation.

Subject Added Entry-Topical Term  

Membranes.

Subject Added Entry-Topical Term  

Fungi.

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Embryos.

Subject Added Entry-Topical Term  

Signal transduction.

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Hair.

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Behavior.

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Plasma.

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Hormones.

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Cytoskeleton.

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Cellulose.

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Insects.

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Families & family life.

Subject Added Entry-Topical Term  

Phosphorylation.

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Yeast.

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Lipids.

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Stem cells.

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Asymmetry.

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Cellular biology.

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Endocrinology.

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Individual & family studies.

Added Entry-Corporate Name  

Stanford University.

Host Item Entry  

Dissertations Abstracts International. 86-03A.

Electronic Location and Access  

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Control Number  

joongbu:656135