טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentMeledin Anna
SubjectCell Non-Autonomous Mechanisms for AFF-1 Mediated Neuronal
Regeneration in C. Elegans
DepartmentDepartment of Biology
Supervisor Professor Benjamin Podbilewicz
Full Thesis textFull thesis text - English Version


Abstract

Caenorhabditis elegans proteins EFF-1 and AFF-1 are somatic cell-cell fusogens that fuse several types of cells and their expression pattern, activities and regulation are known. C. elegans also shows remarkable neuronal regenerative capabilities in axons and dendrites, which vastly decline with aging. The dendritic reconnection process is far less studied, and is suggested to be mediated by AFF-1-containing vesicles that fuse the damaged dendrite ends in a non-cell autonomous manner. Therefore, we tested whether external supply of AFF-1 can improve dendrite regeneration in aged worms.  For this purpose, we constructed AFF-1-coated viral particles with a fluorescent reporter for viral infection, and injected them into worms. We found that first, AFF-1-coated viruses target cells known to express EFF-1 or AFF-1, and demonstrated that this infection requires the expression of a functional fusion protein on the target cell. Second, this tissue-specific infection by AFF-1-coated viruses increased with longer induction period of EFF-1 function in the worm. Third, ectopic EFF-1 expression in the non-syncytial worm’s body wall muscle cells produces muscle syncytia and results in body wall muscle cells infection by AFF-1-coated viruses.  Fourth, AFF-1-coated viruses infected different glia cells, but we could not observe infection of neurons. Nevertheless, injection of AFF-1-coated viruses into aged worms with injured dendrites showed increased neuronal reconnection. Altogether, this work establishes AFF-1-coated pseudotyped viruses as a tissue-specific delivery system for different applications, possibly including neuronal regeneration.