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Transcriptional regulation in the development of the cerebellum and cerebellar granule cells

University of British Columbia

The cerebellum is critical for motor functions such as coordination, precision and accurate timing of movement; as well as non-motor functions including cognitive and emotional processes. During cerebellar development, genesis and fate decisions of cerebellar neural precursors are controlled by genetic networks consisting of transcription factors and their downstream targets. The objectives of my thesis are: 1) to construct the transcriptional network of the developing cerebellum based on gene expression and gene regulation; 2) to investigate the temporally regulated usage of alternative promoters in cerebellar development; 3) to generate a cerebellar granule cell specific transcriptome dataset to identify genes that are dynamically expressed, or significantly enriched in cerebellar granule cells during development; and 4) to study the roles of a newly discovered, dynamically expressed transcription factor - Kruppel-like Factor 4 (Klf4) in cerebellar granule cell development. Taking advantage of high-throughput next generation sequencing technology, we used HeliScopeCAGE, which combines single molecule fluorescent sequencing technology (Helicos) and Cap Analysis of Gene Expression (CAGE), to generate a new transcriptome time series for cerebellar development. We were able to discover hundreds of gene regulators that are important for cerebellar development through differential expression and motif activity analyses. In addition, I analyzed the temporal shift of usage in alternative promoters of a gene, and found that different forms of gene products have distinct functions during cerebellar development. Furthermore, to study the granule cell-specific transcriptome, I used laser microdissection to isolate granule cells from the cerebellum. Comparison of the granule cell transcriptome with the whole cerebellar transcriptome allowed me to identify genes that are dynamically regulated or significantly enriched in the granule cells. Lastly, I studied a mouse knock-out model of Klf4, a potentially key gene regulator from previous analyses, and found that Klf4 does, in fact, have an important role in early granule cell proliferation. This work also showed that Klf4 is involved in the regulation of other important granule cell transcription factors such as Pax6 in the cerebellum for the first time.

Text

2017-04-24

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/61343

Medical Genetics

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/