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Show posters on the hill Investigating Neuronal Differentiation Involving a Novel Xenopus laevis Gene Loss-of-Function Analysis Kaitlyn Le, Mary A. Logan, Monica Vetter Department of Neurobiology and Anatomy Iii]eluni ul 3-1 \|() into a V-iKijiiiv cml'i\u. .in African f CFP DAI'l-slaiited nutkus Merged Gc*t3-1 expression restricted 10 k^hi- .uni.tuiin- ihih.>u.«I differentiation Investigating Neuronal Differentiation Involving a Novel Xenopus laevis Gene Loss-of-Function Analysis Kaitlyn Le, Mary A. Logan, Monica Vetter Department of Neurobiology and Anatomy A central question in nervous system development concerns the mechanisms by which a wide range of neuronal cell types are generated from a common pool of progenitors. Although we know that stem cells can differentiate to form neurons, the genes and molecules that regulate this process are unclear (Gangemi et al). bHLH (basic-helix-loop-helix) transcription fac- tors, which are critical regulators of neuronal differentiation (Bertrand et al), have highly defined expression in the developing retina (Vetter et al). Though it is apparent that proneural bHLH factors have a conserved function across species to drive a program of neuronal differentiation, little is actually known about the cellular mechanisms by which this occurs. Thus, identifying gene targets of the proneural transcription factors will reveal to us the molecules which are responsible for turning stem cells into neurons. A novel gene referred to as Gen. e 3-1 was isolated from a large scale differential display screen to identify gene targets of two Xenopus laevis (XL) proneural transcription factors (Mary Logan, personal communication). In situ hybridizations identified areas in which Gene 3-1 is expressed: particularly regions containing differentiating neurons. We discovered that 3-1 is seen most intensely in the retina, specifically in the neural retina which contains several types of neurons but not in non-neurallens or skin. To determine the effect of loss of Gene 3-1 function during development, morpholino antisense oli-gonucleotides (MO) were used to knockdown expression of the gene and XL's retinal morphology was analyzed. We found that cells injected with the 3-1 MO were less likely to contribute exclusively to retina when compared to the control GFP alone injected cells, suggesting that Gene 3-1 plays a critical role in neurogenesis. Transplantation of stem cells is an exciting, but unperfected, treatment strategy for neurodegenerative diseases. Discovering the molecular mechanisms of stem cell differentiation, including the role of Gene 3-1, has great implications for improving this treatment method. |