Project Details
Abstract
Ribosome is the site for protein translation in both prokaryotes and eukaryotes. However, in contrast to the presence of nucleolus which is the factory for ribosome biogenesis in eukaryotes, there is no obvious nucleolus in prokaryotes. How the nucleolus was evolved from prokaryotes to eukaryotes is one of the significantly unanswered issues in cell biology. Several other questions regarding the nucleolus remain unsolved, such as why organisms have different sizes of nucleoli in different tissues and in tumor cells which have enlarged nucleoli or increasing number of nucleoli as compared with their normal counterparts. Hermaphrodites of Caenorhabditis elegans possess 959 somatic cells, in which intestine cells have the largest nucleolus while neuron cells have the smallest one, which provides a wonderful model to answer how the nucleolus-size is controlled. One C. elegans mutant called ncl-1 appears enlarged nucleoli in neurons and hypodermis cells. In the last few years, we created several strains of worms to reveal a genetic network of let-7-ncl-1-fib-1 that modulates the nucleolar size in C. elegans. By the measurement of nucleolar size of -2 oocyte and hypodermis cell 10 and calculation of intensity of FIB-1::GFP, we also obtained preliminary results indicating that cep-1, ced-4 and ced-3, key members of apoptotic pathway, might be involved in nucleolar size control and the amount of fibrillarin. In addition, by using RNAi feeding method, we found one of RNA helicase (Brr2) which is also a regulator of nucleolar size. In this 2-year grant application, we will continue the previous theme of nucleolus size regulation as follows, 1) to distinguish whether ced-3 is independent from cep-1 or under the regulation of cep-1 in controlling the nucleolar size and the amount of fibrillarin (FIB-1), 2) to verify whether the fibrillarin (FIB-1) is the substrate of CED-3, 3) to establish CRISPR/cas9 system for deletion of RNA helicase of Brr2 gene and insertion a GFP (or mCherry) in the Brr2 gene. In addition to using genetic approaches, biochemistry and cell biology tools will also be applied. By the end of project, we hope we will clarify how cep-1, ced-3 and RNA helicase involve in the nucleolus-size control and the obtained results can be extended to cancer cell biology studies. Most importantly, if our finding that CED-3 regulates fibrillarin and nucleolus size and function is true, it will change the paradigm of CED-3, which can play a positive regulator in cell death and a negative role in ribosome biogenesis.
Project IDs
Project ID:PA10408-0733
External Project ID:MOST104-2311-B182-005
External Project ID:MOST104-2311-B182-005
Status | Finished |
---|---|
Effective start/end date | 01/08/15 → 31/07/16 |
Keywords
- nucleolus
- transgenic worms
- genetic approach
- CEP-1
- CED-3
- GFP
- CRISPR/Cas9
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