LE3 .A278 2010

2010

Vanderluit, Jacqueline

Acadia University

Bachelor of Science

Honours

Biology

Biology

The neural precursor population, from which neural cells are derived, is tightly regulated by cell division and cell death ( apoptosis). Myeloid cell leukemia- 1 ( Mcl- 1) is an anti- apoptotic member of the Bcl- 2 family which acts at the initial stages of apoptosis. Recent work with Mcl- 1 conditional knockout mice revealed that Mcl- 1 is required for the survival of embryonic Nestin positive neural precursor cells. These cells include both neural progenitor cells and neural stem cells. In this research project, I considered whether Mcl- 1 was a survival factor specifically for mammalian embryonic neural stem cells. To address this question, both loss- of- function and gain- of- function strategies were employed. The in vitro neurosphere assay revealed that Mcl- 1 conditional knockout embryos had significantly fewer self- renewing neural precursor cells, suggesting that Mcl- 1 is a survival factor for embryonic stem cells. In utero electroporation was employed to examine Mcl- 1 gain- of- function in vivo. Enhanced Mcl- 1 protein was observed in only a few cells and was compartmentalized within the cell in brains electroporated with the Mcl- 1 plasmid. In contrast, transfection with mutant Mcl- 1 plasmid ( proteasome- resistant) enhanced Mcl- 1 protein levels in all transfected cells demonstrating that protein levels are regulated by the proteasome. 48 hours after electroporation there was a 2- fold increase in transfected cells that had exited the cell cycle and migrated to the cortical plate in mutant Mcl- 1 transfected brains compared to control. Furthermore, Mcl- 1 gain- of- function resulted in a 3- fold increase in newborn neurons in the developing cortex within 48 hours. These results show that Mcl- 1 is tightly regulated and functions to promote both survival and neurogenesis in the embryonic neural precursor population.

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https://scholar.acadiau.ca/islandora/object/theses:716