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76 These findings provide a comparative basis to understand the evolutionary origins and regulatory biology of vertebrate hematopoiesis in the context of a tractable gene regulatory network model. Program/Abstract # 230 Role of ADAM metalloproteases in craniofacial development of zebrafish Cousin, Helen; Karlstrom, Rolf, (Univ of Massachusetts, Amherst, United States); Thisse, Christine; Thisse, Bernard (University of Virginia, Charlottesville, United States); Alfandari, Dominique (Univ of Massachusetts, Amherst, United States) The cranial neural crest (CNC) cell is a population of pluripotent cells originating from the dorsal part of the future brain. They migrate ventrally along define pathways and give rise to the majority of the craniofacial structures. Defects in the migration and differentiation of these CNC cells lead to either lethality or a wide range of craniofacial defects. We have identified in the frog Xenopus laevis many proteins involved in CNC migration, including 3 members of the ADAM (A Disintegrin and Metalloprotease) family: ADAM9, 13 and 19. The two main functions of these ADAM are to cleave cell surface proteins like Cadherin-11 and to control the expression of genes like Calpain8-a. While the CNC of all vertebrates migrate and give rise to the future face, Xenopus CNC display some peculiarities. Frog CNC displays a biphasic migration pattern (first migrating as a cohesive sheet of cells before migrating as single cells) while most other species’ CNC migrate as single cells. In order to further our understanding of the role of these ADAM during craniofacial development across species, we propose to study the role of these ADAM proteins in other vertebrate species whose behavior closely resembles the behavior of human CNC. The Zebrafish is an ideal model system to study this question. We present the expression pattern of the ADAM9, 12, 13 and 19 in Zebrafish as well as the analysis of the knock down of the single or combined knock down of these ADAM. The differences and similarities of the morphotypes between zebrafish and Xenopus will be presented. The implications on the functional evolution of ADAM during the craniofacial formation in vertebrates will be discussed. Program/Abstract # 231 Intracellular localization and regulation of matrix metalloproteinase 2 in zebrafish muscle Fallata, Amina, University of New Brunswick, Fredericton, Canada Matrix metalloproteinases (MMPs) are zinc-dependent proteases best known for their roles in extracellular matrix remodeling. However, recent evidence has revealed the localization of MMP-2 (Gelatinase A) within rat cardiac myocytes, where it degrades protein components of the sarcomere under conditions of oxidative stress during ischemia/reperfusion injury. Also, human MMP-2 activity is regulated by phosphorylation, which is characteristic of intracellular enzymes. The objectives of my research are to determine if these unexpected intracellular roles of Gelatinase A are evolutionarily conserved in vertebrate muscle, and if so, to establish the zebrafish as a model system for their study. Using confocal and electron microscopy, I have obtained evidence that zebrafish Mmp2 is present in sarcomeres of skeletal muscle. I will use 32P metabolic labeling and immunoprecipitation to determine if Mmp2 is phosphorlated in zebrafish. Ultimately, I plan to investigate the physiological roles of Mmp2 in muscle cell development and physiology. Program/Abstract # 232 Swim-training changes the spatio-temporal dynamics of skeletogenesis in zebrafish larvae (Danio rerio) Fiaz, Ansa, Wageningen University Experimental Zoology, Wageningen, Netherlands; Léon-Kloosterziel, Karen M.; Gort, Gerrit (Wageningen University, Wageningen, Netherlands); Schulte-Merker, Stefan (Hubrecht Institute-KNAW & UMC Utrecht and Wageningen University, Utrecht, Netherlands); van Leeuwen, Johan L.; Kranenbarg, Sander (Wagening, Netherlands) Fish larvae experience many environmental challenges during development such as variation in water velocity, food availability and predation. The rapid development of structures involved in feeding, respiration and swimming increases the chance of survival. It has been hypothesized that mechanical loading induced by muscle forces plays a role in prioritizing the development of these structures. Mechanical loading by muscle forces has been shown to affect larval and embryonic bone development in vertebrates, but these investigations were limited to the appendicular skeleton. To explore the role of mechanical load during chondrogenesis and osteogenesis of the cranial, axial and appendicular skeleton, we subjected zebrafish larvae to swim-training, which increases physical exercise levels and presumably also mechanical loads, from 5 until 14 days post fertilization. Here we show that an increased swimming activity accelerated growth, chondrogenesis and osteogenesis during larval development in zebrafish. Interestingly, swim-training accelerated both perichondral and intramembranous ossification. Furthermore, swim-training prioritized the formation of cartilage and bone structures in the head and tail region as well as the formation of elements in the anal and dorsal fins. This suggests that an increased swimming activity prioritized the development of structures which play an important role in swimming and
77 thereby increasing the chance of survival in an environment where water velocity increases. Our study is the first to show that already during early zebrafish larval development, skeletal tissue in the cranial, axial and appendicular skeleton is competent to respond to swim-training due to increased water velocities. It demonstrates that changes in water flow conditions can result into significant spatio-temporal changes in skeletogenesis. Program/Abstract # 233 Epigenetic restriction of neural crest emigration by DNMT3B Hu, Na, Caltech Biology Pasadena, United States The neural crest is a multipotent stem cell-like population that emigrates from the central nervous system (CNS) to populate diverse derivatives including peripheral ganglia and the craniofacial skeleton. Although there are numerous studies regarding initiation of the process of neural crest emigration from the dorsal neural tube, far less is known about why the emigration process stops. Here, we show that an epigenetic modifier, DNMT3B, influences the timing of neural crest emigration. We find that DNA methyl transferase 3B is expressed in the dorsal neural tube and migratory neural crest cells during stages of neural crest migration and differentiation. Normally, EMT of the cranial neural crest is complete by stage 11. Interestingly, morpholino-mediated knockdown of DNMT3B prolongs the time of emigration from the neural tube, but has no effect on initial neural crest specification. At later stages, this is manifested in extra neural crest cells and their premature differentiation in the trigeminal ganglion. In contrast, DNMT3B morpholino does not alter the numbers of proliferating cells. Consistent with the intriguing possibility is that DNMT3B plays a role in EMT, Snail2 is upregulated after loss of DNMT3B. Since neural crest EMT is prolonged by knock-down of DNMT3B, we hypothesize that DNMT3B plays a role in repressing the process of EMT from the neural tube at the proper time. Program/Abstract # 234 Investigating the roles of the Argonaute CSR-1 in modulating chromatin and building kinetochores Wedeles, Christopher; Claycomb, Julie M., University of Toronto, Canada The CSR-1 pathway (Chromosome Segregation and RNA Interference Deficient) is a small RNA pathway in C. elegans that is required for proper chromosome segregation and kinetochore formation. The pathway requires several factors that are also required for RNA interference, including the Argonaute CSR-1. CSR-1 associates with small RNAs, called 22G- RNAs, which are antisense to approximately 4200 germline-expressed protein coding genes. Unlike Argonautes in canonical gene-silencing pathways, CSR-1 does not affect the steady state levels of target mRNAs or proteins. Instead, CSR-1 associates with its target gene loci, which are adjacent to genomic regions that are enriched for the conserved centromeric histone H3 protein, CENP-A/HCP-3. Loss of the CSR-1 pathway leads to the disorganization of kinetochore proteins, including HCP-3. We hypothesize that CSR-1 and the 22G-RNAs are involved in organizing chromatin domains that are essential for chromosome segregation. We have validated several histone modifications that are enriched at CSR-1 targeted chromosomal loci. Interestingly, these modifications are characteristic of euchromatin and transcriptionally active regions of the genome. These observations are consistent with recent findings in which euchromatic histone modifications and transcription within the core centromeric chromatin play key roles in maintaining centromere function in several species, including humans. As such, we are investigating the relationship between CSR-1, the 22G-RNAs, these euchromatic histone modifications and transcription to determine their roles in kinetochore formation throughout animal development. Program/Abstract # 235 Dissecting the role of D2096.8/NAP-1 in small RNA-mediated chromatin regulation Francisco, Michelle Ann; Claycomb, Julie M., University of Toronto, Canada; Small RNA-mediated gene-silencing pathways related to RNAi are critical regulators of gene expression throughout development. Some of the least understood roles for these small RNA pathways are in modulating chromatin and organizing the genome. An essential small RNA pathway in C. elegans, the CSR-1 pathway (Chromosome Segregation and RNAi Deficient), is required for the formation of functional kinetochores and for proper chromosome segregation. Small RNAs, called 22G-RNAs, guide the Argonaute CSR-1 to interact with specific genomic loci and influence the centromeric chromatin on which kinetochores are built. We hypothesize that this process involves the recruitment of chromatinmodifying proteins, which assist in modulating centromeric chromatin. From a candidate screen of chromatin-related factors implicated in gene silencing, I identified the gene D2096.8/NAP-1, which encodes a homolog of the human Nucleosome Assembly Protein, NAP-1. Loss of D2096.8/NAP-1 results in a set of phenotypes that are unique to the CSR- 1 pathway: mislocalization of germ line P granules, embryonic chromosome segregation defects and RNAi deficiency. A nucleosome assembly protein is an attractive candidate for factors that cooperate with the CSR-1 pathway in regulating centromeric chromatin. Thus, I am conducting a series of experiments to elucidate the roles of D2096.8/NAP-1 in small
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1 Program/Abstract # 1 Role of the
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3 Program/Abstract # 7 Forward gene
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5 Program/Abstract # 13 Evolution a
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7 Program/Abstract # 19 Lethal gian
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9 Program/Abstract # 26 On the comb
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11 Program/Abstract # 32 Imaging in
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13 and electron microscopy studies
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15 paracellular space, and interact
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17 the proximal to distal axis of t
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19 Dominguez-Castellano, Maria; Gar
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21 We are interested in the role of
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23 more likely than students who di
Page 25 and 26: 25 was a significant loss of cells
Page 27 and 28: 27 Fgfr3 expression in the limb cho
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Page 31 and 32: 31 and migration (ADAM13). They act
Page 33 and 34: 33 Program/Abstract # 101 The influ
Page 35 and 36: 35 Program/Abstract # 107 Shroom3-d
Page 37 and 38: 37 Program/Abstract # 113 Requireme
Page 39 and 40: 39 (Queens College, Flushing, Unite
Page 41 and 42: 41 these data imply that Dynamin is
Page 43 and 44: 43 Congenital renal malformations a
Page 45 and 46: 45 Elevated nuclear translocation o
Page 47 and 48: 47 progenitor cells that cover the
Page 49 and 50: 49 abnormally dilated capillaries i
Page 51 and 52: 51 malformations in murine limb bud
Page 53 and 54: 53 Yuqing (Mouse Imaging Centre, To
Page 55 and 56: 55 in the villi at E14. At E11, the
Page 57 and 58: 57 Program/Abstract # 173 The role
Page 59 and 60: 59 Boldt, Clayton, UT Southwestern,
Page 61 and 62: 61 examine stem cell-based CNS rege
Page 63 and 64: 63 Incubation of regenerating cells
Page 65 and 66: 65 learn which dynamic behaviors oc
Page 67 and 68: 67 cell proliferation and for norma
Page 69 and 70: 69 Program/Abstract # 209 Drosophil
Page 71 and 72: 71 cranial neural crest cells, as t
Page 73 and 74: 73 experimental analysis. The jerbo
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Page 79 and 80: 79 into the role snx5 playsin the N
Page 81 and 82: 81 Lee, Hu-Hui, National Chiayi ers
Page 83 and 84: 83 understood. Here, we have establ
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Page 87 and 88: 87 approach. A similar strategy was
Page 89 and 90: 89 verify the functional specificit
Page 91 and 92: 91 Program/Abstract # 278 Heterogen
Page 93 and 94: 93 Program/Abstract # 284 Investiga
Page 95 and 96: 95 Program/Abstract # 290 A molecul
Page 97 and 98: 97 dizygotic twin studies have show
Page 99 and 100: 99 Program/Abstract # 301 Dual role
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Page 103 and 104: 103 Sonic Hedgehog (Shh) is a secre
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Page 111 and 112: 111 that maternally-supplied Lkb1 i
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Page 117 and 118: 117 delayed and stunted as monitore
Page 119 and 120: 119 Program/Abstract # 359 The meth
Page 121 and 122: 121 Misregulation of molecular path
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Page 125 and 126: 125 versus asymmetric cell division
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127 spinal cord. Iulianella, Angelo
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129 determine cell cycle activity i
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131 in expanded Lmx1a/b+ progenitor
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133 ROS levels. Collectively, our r
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135 limbs. Apoptosis was also pertu
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137 Henkels, Julia; Zamir, Evan, Ge
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139 however, and its role in CSF ma
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141 embryonic precursors to form an
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143 with fork retarding Replication
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145 homeodomain (HD) transcription
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147 fate, potentially acting downst
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149 involved in Drosophila ventral
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151 Program/Abstract # 456 Thoracic
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153 ureteric insertion into the bla
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155 of p16, a known cyclin kinase i
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157 rax mutant was recently found i
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Abstracts - Society for Developmental Biology

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