The effects of genome size reduction on cellular processes

点击翻译按钮获取中文摘要

Our own genomes are extremely large, possessing genes that include very long stretches of non-coding sequences called introns. For proper expression to occur, introns are removed, or spliced, from messenger RNAs by a large macromolecular, cellular machine: the spliceosome. However, not all genomes are large like those of humans. Eukaryotes possess a range of genome sizes, including genomes that are highly reduced. As genomes reduce in size, non-coding sequences (such as introns) can be shortened, or lost. Cellular machines are also affected, and undergo reduction by having fewer components and interaction partners. I propose to use a comparative approach to examine splicing in eukaryotes that have independently undergone reduction. Identifying common features of reduced splicing systems in diverse organisms allows prediction of core functional and mechanistic aspects of this process that are otherwise obscured by the myriad components in more complex systems. By strategically focusing on unicellular, free-living red algae and parasitic fungi, I propose to assess the effects of genome reduction on groups of microbial eukaryotes that are unrelated (sharing a very distant common ancestor), have reduced independently from one another, and possess different lifestyles/habitats. Therefore, identifying shared functional and mechanistic aspects of reduced splicing systems in these disparate groups will strengthen my prediction of their core importance, while also ensuring that observations are broadly relevant across eukaryotes. Just as we are challenged to understand the staggering level of organismal diversity on this planet, the underlying diversity of cellular biology is just as varied, fascinating, and complex. By examining a key eukaryotic process in a highly reduced cellular system, we gain insight into both the flexibility of the process, and its mechanistic underpinnings. This research is broadly impactful across diverse fields including cell biology, splicing biochemistry, molecular parasitology and phycology, and microbial genomics.