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Publication Date

Summer 2011

Degree Type

Thesis - Campus Access Only

Degree Name

Master of Science (MS)

Department

Biological Sciences

Advisor

Miri K. VanHoven

Keywords

Neuroligin-1 GRASP

Subject Areas

Neurosciences; Genetics

Abstract

Neurons are specialized cells that make up the nervous system, and their function is to receive, process, and transfer information through junctions called synapses. Upon reaching their target region, most neurites still contact many potential partners. To form functional circuits, individual neurons must correctly identify and form connections with appropriate synaptic partners, a process we call synaptic partner recognition (SPR). To study the molecular mechanisms of SPR, our group developed a genetically encoded fluorescent trans-synaptic marker called NLG-1 GRASP, which labels synapses in the genetic model organism Caenorhabditis elegans. This system allows us to assess synaptogenesis instantly in live animals, making genetic analysis feasible. In this work, we developed accurate and reproducible methods to quantify NGL-1 GRASP fluorescence intensity and neurite contact using ImageJ software. NLG-1 GRASP fluorescence intensity was assessed by measuring total fluorescence intensity, then measuring and subtracting out background fluorescence intensity. The proportion of neurite contact was determined by measuring the length of neurite overlap, subtracting the sum of the lengths of all gaps in neurite contact, and dividing by the length of overlap. Using this approach, we obtained consistent values for both wild-type and mutant animals. Our findings illustrate the potential of this new approach to gene discovery and characterization, and are being used for current studies of SPR.

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