Exploration and Investigation of Brown Adipogenesis-Associated Alternative Splicing Network by Transcriptome Analyses

Adipose tissue is a prominent organ that regulates the nutrient and energy homeostasis. Two functionally distinct types of adipose tissue exist in mammals. White adipose tissue (WAT) efficiently reserves the triglyceride as energy source, whereas brown adipose tissue (BAT) expenditures the energy through thermogenesis and therefore counteract obesity in rodents and infants. The presence and function of BAT in adult human is largely unknown. Apart from the function, the knowledge of regulatory mechanism and factor involved in the development of BAT is sparse. Alternative splicing (AS) functions as a prevalent mechanism in expanding the genetic diversity of eukaryotic cells. Approximately 90% of human genes generate more than one transcript through this meticulously controlled process. The interplay between splicing factors and cis-elements constitutes the molecular mechanism in programming the splicing profile in spatiotemporal manners. RBM4 is demonstrated as the splicing factor to modulate the brown adipocyte-related splicing profiles which largely contributes to the development of brown adipose tissue. The reduced mass of brown adipose tissue of Rbm4-/- mice prompts the following investigation into the possible function of RBM4 on brown adipogenesis-related slicing network. These results have been published in BBA-Molecular Cell Research and RNA Biology journal. The major purpose of this project is to reveal more adipogenesis-associated splicing event during the development of BATs by using deep RNA sequencing. To identify the potential splicing factor involved in adipogenesis-related splicing event, the end-labeled RNA oligo derived from the BAT-related transcripts will be incubated with cell lysates prepared from the proliferating or differentiating C3H10T1/2 cells. The precipitated factor will be characterized by using proteomics approach. Subsequently, the characterization of splicing factor-specific target will be next conducted using CLIP sequencing. I anticipate the result of this project would establish the alternative splicing cascade and therefore bring a comprehensive scope on the post-transcriptional regulation of BAT development. Moreover, the results may suggest the therapeutic potential of brown adipocytes for combating metabolic diseases and obesity in future.