@article{THESIS,
      recid = {10129},
      author = {Shi, Zhuoyue},
      title = {The Essential Role of m6A mRNA Methylation and m6A Reader  Protein YTHDF1 in Maintaining Cell-Type Specific Functions  in the Basal Ganglia},
      publisher = {University of Chicago},
      school = {Ph.D.},
      address = {2023-12},
      number = {THESIS},
      pages = {113},
      abstract = {The N6-methyladenosine (m6A) methylation, identified in  the 1970s, has become increasingly understood with the  development of recent high-throughput sequencing  techniques. The discovery of its distinct distribution and  associated effectors has enabled many functional studies on  this reversible modification. m6A methylation plays an  essential role in the post-transcriptional regulation of  mRNA, dynamically influencing mRNA metabolism and various  cellular functions.In neurons, precise control of protein  synthesis is crucial during the activity-dependent  transportation of mRNAs. Thus, post-transcriptional  regulation offers a potentially ideal mechanism to  dynamically drive local translation in neurons, allowing  synaptic plasticity regulation and dendritic remodeling.  m6A level dramatically increases by adulthood, suggesting  its unique role in the adult brain, which is a topic just  beginning to be systematically studied.
For my thesis, I  take advantage of the fact that there are only two  prominent neuronal cell types throughout the striatum: the  dopamine (DA) D1 and D2 receptor-expressing medium spiny  projection neurons (SPNs). Moreover, D1 and D2 SPNs have  well-documented opposing functions in motor control,  simplifying the molecular studies and allowing comparison  of behavioral phenotypes.
In the first part of my thesis,  by using transgenic mouse models with selective deletion of  Mettl14 in D1 and D2 SPNs, I found that Mettl14 deficiency  blunted responses to environmental challenges at cellular  and behavioral levels in the adult brain.
One of m6A  modification’s downstream reader proteins, YTHDF1, has been  shown to promote protein synthesis in neurons and regulate  synaptic plasticity and learning. However, it is unclear if  YTHDF1 is the primary downstream mediator of m6A function  in the brain. In the second part, I found that Ythdf1  deletion in D1 and D2 SPNs resembled the behavioral  impairments caused by Mettl14 deletion in a cell  type-specific manner, suggesting YTHDF1 as the primary  mediator of the functional consequences of m6A modification  in the striatum. Moreover, striatal neurons from Ythdf1  constitutive knockout mice were incapable of adapting to  environmental challenges.
DA affects striatal neuronal  activity and regulates corticostriatal plasticity. In the  third part, I examined the role of m6A mRNA methylation in  dopaminergic neurons. I found that in all three cell types:  D1-SPNs, D2-SPNs, and dopaminergic neurons, Ythdf1 deletion  resembled the behavioral impairments caused by Mettl14  deletion. Down-regulation of m6A is found to induce cell  apoptosis in the dopaminergic cells in vitro. However, I  found no significant difference in tyrosine hydroxylase  (TH)-positive cell number in the midbrain of Mettl14  conditional knockout mice. This suggests that m6A depletion  did not cause dopaminergic neuron degeneration in any age  group.
The fourth part is our ongoing experiments to  examine the role of m6A modification in maintaining cell  identity and normal functions in the adult brain. I found  that Mettl14 deletion in D1-SPNs caused behavioral  impairments in an age-dependent manner, suggesting the  significance of m6A increases as the mice age. In the  future, we plan to explore the expression profile of the  transcription factors (TFs) and track the temporal features  of m6A distribution on these genes in D1 and D2 SPNs. },
      url = {http://knowledge.uchicago.edu/record/10129},
      doi = {https://doi.org/10.6082/uchicago.10129},
}