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Expansion mutation within polyglutamine (polyQ) tract proteins is known to underlie a number of severe neurodegenerative disorders such as Huntington’s Disease and Spinocerebellar Ataxia. One of the pathologic hallmarks of polyQ expansion disease is the aggregation of mutant proteins into intracellular inclusion bodies. Our lab is actively investigating FAM171B- a relatively uncharacterized protein that also contains a stretch of consecutive glutamines within its primary amino acid sequence and is likely expressed in the nervous system. Since it too contains a short polyQ stretch, we surmised that FAM171B may also be recruited into polyQ aggregates formed by known pathologic proteins. To test this hypothesis, we transfected cells with an expanded version of SCA7-GFP to form intracellular aggregates, and utilized FAM171B specific antibodies, immunofluorescence, and confocal microscopy to assay FAM171B’s intracellular location in relation to the SCA7 inclusion bodies. Our findings indicate that a portion of FAM171B does indeed alter its normally dispersed cytoplasmic subcellular distribution into SCA7 aggregates that locate near the peri-nuclear region of human glioblastoma tissue culture cells. Thus, the novel protein FAM171B may play a role in the molecular mechanisms underlying polyQ disease pathology. 

Hexavalent chromium (Cr6+) is a common environmental pollutant extensively used in industrial processes like chrome-plating, leather tanning, and paint making that is capable of accumulating in aquatic vascular plants and tissue of animals. The uneven geographical distribution of chromite mining makes this issue a global one and indicates that further study of Cr6+ may lead to targeted treatment in individuals who ingest contaminated water and wildlife or suffer from direct skin contact with contaminated soil. Dictyostelium discoideum is a soil-dwelling eukaryote that contains many genes that are homologous to human genes while exhibiting a simple lifecycle, restricted cell types and behaviors, and rapid growth. Dictyostelium is widely regarded as a good model organism for studying eukaryotic cell response to toxic compounds. The aim of the study is to determine how hexavalent chromium affects cytoskeletal proteins, specifically actin, and the movement of Dictyostelium in response to Cr6+. A focus is placed on actin and its associated proteins because it has been shown to be a key player specialized stress signaling pathways, and its associated proteins may be multifunctional and may be implicated in a variety of conditions. Chemotaxis, cell movement in response to an external stimulus, was assayed following cell treatment to determine how cell signaling changes as a result of Cr6+ exposure altered the assembly of the actin network. Differences in the actin network of both the treatment and control groups were visualized using fluorescence microscopy. Electrophoresis was then performed on control and treatment groups to resolve proteins and identify specific changes in the expression of actin and its associated proteins. 

Expansion mutation within polyglutamine (polyQ) tract proteins is known to underlie a number of severe neurodegenerative disorders such as Huntington’s Disease and Spinocerebellar Ataxia. Using a bioinformatics approach, we have identi􀃕ed a novel protein, FAM171B, that contains a stretch of 14 consecutive glutamines. Using in situ hybridization and immunohistochemistry experiments, our data strongly suggests that FAM171B is widely expressed in the brain with abundant expression in the hippocampus, cortex, and cerebellum. To begin elucidating FAM171B sub-cellular location we are using confocal 􀃖uorescence imaging of GFP-fusion tagged FAM171B and anti-FAM171B antibodies in vitro. Our 􀃕ndings indicate that FAM171B displays a punctate/vesicular staining pattern throughout the cytoplasm of human glioblastoma tissue culture cells and primary mouse cortical neurons. FAM171B localization is particularly enriched in the peri-nuclear region and adjacent to the plasma membrane. Current studies are utilizing organelle speci􀃕c markers to verify sub-cellular locale and live-cell imaging to assay whether FAM171B may tra􀃞c between intracellular compartments. 

It has been well supported among mammalian species that the hypothalamicpituitary- gonad (HPG) axis is regulated positively by kisspeptin and negatively by gonadotropin inhibitory hormone (GnIH). Studies with seasonal breeding models have generally shown higher levels of kisspeptin in areas of the hypothalamus associated with reproduction, such as the preoptic area (POA) and arcuate nucleus, during the breeding season. Conversely, when examining models during the non-breeding season, studies have indicated GnIH to be higher in hypothalamic nuclei, such as the POA. However, kisspeptin’s role in regulating reproduction may not be consistent among all vertebrate groups. While kisspeptin has been shown to upregulate reproduction in mammals, this peptide has not been detected in avian species and recent work in 􀃕sh has suggested that kisspeptin may not play a regulatory role in reproduction. Relatively little is known about these peptides in reptiles and the seasonal regulation of kisspeptin and GnIH has not been investigated in this group. Green anole lizards (Anolis carolinensis) have a distinct breeding and nonbreeding season, and during the breeding season, steroid hormone levels in the plasma are elevated, males are more territorial, and display reproductive behaviors at a higher frequency. Previous work in this species has demonstrated that, in non-breeding anoles, kisspeptin-positive neurons were present in the POA and the dorsomedial hypothalamus. It is currently unknown whether kisspeptin expression is altered in breeding lizards and there is no data available on GnIH expression in this species. We hypothesize that there is a seasonal effect on kisspeptins and GnIH in green anole lizards, with kisspeptins more highly expressed in the breeding season, while GnIH is more highly expressed in the non-breeding season. Preliminary data using quantitative PCR has revealed no signi􀃕cant di􀃠erence between seasons in the expression of kiss1, kiss2, and Gnih mRNA from a dissection of the brain that contained the hypothalamus (F ≤ 4.35, p ≥ 0.053, n = 4-6 per group). Although we did not detect a significant difference between seasons, expression in specific regions may differ. Therefore, using fluorescent in situ hybridization, we aim to determine the localization and expression levels of kiss1, kiss2 and Gnih expression throughout the hypothalamus. This study expands upon available data and bridges the evolutionary gaps in the roles of kisspeptin and GnIH in regulating reproduction. 

Insufficient thyroid hormone (TH) during development results in permanent neurological deficits. These deficits are the result of neuroanatomical defects that include smaller brain, fewer parvalbumin neurons, and hypomyelination. Interestingly, insufficient insulin-like growth factor 1 (Igf-1) during development results in similar neuroanatomical defects to those reported for developmental hypothyroidism. Thyroid hormone is known to indirectly influence serum Igf-1 levels through its regulation of pituitary growth hormone (GH) secretion which stimulates hepatic Igf-1 production. Our lab and others have observed decreases of local brain-derived Igf-1 in the developing hypothyroid mouse brain. This observation suggests that deficits associated with low TH during development may be the result of altered brain-derived Igf-1. Considering this, we sought to determine whether ectopically expressing Igf-1 in the developing brain could rescue neuroanatomical defects associated with TH. To accomplish this, the tet-off transgenic system was used where mice harboring tetracycline transactivator protein driven by the human GFAP promoter (tTA-GFAP) were crossed with mice containing the human Igf-1cDNA under the control the TET response element (Igf1-pTRE) transgene. Double transgenic (dTg) offspring carrying both the tTA-GFAP and Igf1-TRE genes overexpress Igf-1 specifically in brain astrocytes. The timed-pregnant mice were treated with thyroid gland inhibitors from embryonic day 14.5 (E14.5) until postnatal day 14 (P14) to induce a hypothyroid state in pups. At P14, pups were weighed and sacrificed, trunk blood was collected, and brains were dissected, weighed, and immediately frozen. Hippocampal structure, known be disrupted by developmental hypothyroidism, was assessed by fluorescent imaging using DAPI staining. Our initial results indicate that ectopic expression of Igf-1 in the brain (dTg mice) rescues hypothyroidism-induced reductions in brain weight without increasing body weight. In addition, the ectopic expression of Igf-1 restored hypothyroidism-induced perturbations in dentate gyrus size. Ongoing studies are using quantitative real-time PCR on micro-dissected cortical and hippocampal samples, to quantify myelin associated glycoprotein and parvalbumin mRNAs. Taken together, our findings support the idea that ectopic brain-derived Igf-1 rescues neuroanatomical defects caused by hypothyroidism and implicates TH in the regulation of brain Igf-1.