Lacerda, Andressa

Iridoviruses are large (120-200nm) double stranded DNA viruses that contain an icosahedral capsid. The iridoviridae family is composed of five genera that infect a wide range of poikilothermic vertebrates (Lymphocystivirus, Ranavirus and Megalocyivirus) and invertebrate hosts (Iridovirus, Chloriridovirus). Frog virus 3 (FV3) is a member of the Ranavirus genus, and is commonly used as a model system to study iridoviruses. I was interested in understanding virus-host interaction in FV3. I studied two viral genes, FV3 97R and FV3 75L. Here I demonstrate that 97R localizes to the endoplasmic reticulum (ER) at 24 hours post-transfection. However, at 35 hours post-transfection 97R localizes to the ER but also begins to form concentrated pockets, continuous with the nuclear membrane This study found that 97R possess a unique phenotype and that its localization to the ER is mediated through its C-terminus transmembrane domain. FV3 75L encodes an 84 amino acids protein. I showed that FV3 75L localizes to the early endosomes, while its cellular binding partner, LITAF, localizes to late endosome/lysosome. Interestingly, when FV3 75L and LITAF are co-transfected into cells, LITAF can alter the subcellular localization of FV3 75L to late endosome/lysosomes. A physical interaction between LITAF and FV3 75L was demonstrated through a pull-down assay and that a highly conserved domain found in both proteins may mediate the interaction. LITAF has been proposed to function in protein degradation, but there is still uncertainty on LITAF's specific role. I was interested in further characterizing LITAF and its implications in protein degradation and a neurodegenerative disorder. At least 9 mutations of LITAF are associated with Charcot-Marie-Tooth disease type 1C (CMT1C), which belongs to the group of most common heritable neuromuscular disorders, affecting approximately one in 2500 people. We show that LITAF mutants G112S and W116G mislocalize from the late endosome/lysosome to the mitochondria while the T49M and P135T mutants show partial mislocalization with a portion of the protein present in the late endosome/lysosome and a portion of the protein localized to the mitochondria. Since LITAF is believed to play a role in protein degradation, it is possible that the specific characteristics of CMT1C may occur though impaired degradation of Schwann cell membrane proteins, such as PMP22. I was able to show that when WT LITAF is present, there is a decrease in the PMP22 intracellular levels, which suggest that LITAF plays an important role in protein degradation, and also in other types of CMT. Insight into how mutations in LITAF cause CMT1C may not only help better understand cellular pathways, but also further elucidate the role LITAF's viral homolog FV3 75L during viral infection.

Author Keywords: 75L, Charcot-Marie-Tooth, CMTC1, ER, FV3, LITAF

2015 Ph.D. grad Andressa Lacerda is in mid-career stride, despite being only 26. She's a founding partner and the CFO in Noble Inc., a company that will manufacture and distribute filtration systems to remove nanosilvers from wastewater as well as introduce pharmaceuticals that will cure cancer and diseases that are caused by virus'. Her partner in this is Adam Noble, a whiz-kid who has set both the Trent community and world on fire with research that he accomplished in the labs at the university when he was just a high school student. \n\nAndessa helped mentor Adam into becoming one of Canada's "20 Under 20" in 2014. Together they have just signed on as cornerstone tenants of Trent University's new Research and Innovation Park, with a $20 million, 50,000-square-foot production facility to be built soon.\n\nAndressa's own research has shed new light onto neurological disorders – in particular how mutations of LITAF protein cause the genetic Charcot-Marie-Tooth disease. \n\nIt's a fascinating discussion – and one where another of Andressa's talents shine: the ability to take complex ideas and make them relatable to students and laypeople.,Original location: http://trenttalks.podbean.com/e/trent-voices-episode-31-andressa-lacerd…