Evolutionary Conservation of the Heterochronic Pathway in C. elegans and C. briggsae

Heterochronic genes control the sequence and timing of developmental events during four larval stages of Caenorhabitis nematodes. Mutations in these genes may cause skipping or reiteration of developmental events. C. briggsae is a close relative of C. elegans. These species have similar morphology and share the same ecological niche. C. briggsae undergoes the same developmental pathway consisting of four larval stages before reaching adulthood. It also has the same set of heterochronic genes. Lin-28 is one of the heterochronic genes that also exists in other animals from flies to humans. It conservatively blocks the maturation of let-7 miRNA, the process is generally associated with the stem cell state. lin-28 is silenced as cells differentiate. C. elegans mutants of lin-28 have a reduced number of seam cells and precocious alae. Despite the highly conserved protein sequence, C. briggsae develop a distinct phenotype when its lin 28 is disrupted. Worms did not have a characteristic vulval development defect, they also became lethargic and had a reduced fertility. This observation led to a question of how conserved the heterochronic pathway is in close species

LRP-2 controls the localization of C. elegans SYS-1/beta-catenin

The polarity of the C. elegans P7.p cell divisions is controlled by the Wnt/β-catenin asymmetry pathway (Green et al., 2008; Minor et al., 2013). This pathway includes the β-catenin-like proteins SYS-1 and WRM-1, POP-1/TCF, and the Nemo-like-kinase, LIT-1 (reviewed by Mizumoto and Sawa, 2007). The Wnt/β-catenin asymmetry pathway ensures different ratios of SYS-1 to POP-1, controlling the differential transcription of Wnt target genes between daughters of an asymmetric cell division. Because our genetic data indicate an antagonism between LRP-2 and LIN-17 similar to that between CAM-1 and VANG-1 and LIN-17 (Minor and Sternberg, 2019), we wanted to determine if LRP-2 can control the asymmetric localization of SYS-1 between the daughter cells of P7.p during anaphase of the first cell division. The initial establishment of vulval polarity can be observed through the localization of VENUS::SYS-1 (VNS::SYS-1), localized in a high (P7.pa)/low (P7.pp) pattern in the wild-type worm, reciprocal to the localization of POP-1/TCF (Phillips et al., 2007; Green et al., 2008). It was previously reported (Green et al. 2008) that VNS::SYS-1 asymmetry in P7.p daughter cells is often lost in lin-17(n671) and lin-18(e620) mutants. These mutants display two aberrant patterns of VNS::SYS-1 localization as well as the wild-type pattern, though less frequently. The two deviant localization patterns include one in which both P7.pa and P7.pp express equal amounts of VNS::SYS-1 and a reversed VNS::SYS-1 pattern in which P7.pp is enriched with VNS::SYS-1. By observing VNS::SYS-1 localization in a lin-17(n671); lrp-2(gk272) background we see that the aberrant localization of SYS-1 is suppressed to a similar degree to that of lin-17(n671); cam-1(gm122) and lin-17(n671); vang-1(ok1142). This observation confirms LRP-2 controls vulval cell polarity by antagonizing LIN-17 in a similar fashion to CAM-1 and VANG-1, and that the effect of LRP-2 is at the level of P7.p rather than its progeny

LRP-2 controls the localization of C. elegans SYS-1/beta-catenin

The polarity of the C. elegans P7.p cell divisions is controlled by the Wnt/β-catenin asymmetry pathway (Green et al., 2008; Minor et al., 2013). This pathway includes the β-catenin-like proteins SYS-1 and WRM-1, POP-1/TCF, and the Nemo-like-kinase, LIT-1 (reviewed by Mizumoto and Sawa, 2007). The Wnt/β-catenin asymmetry pathway ensures different ratios of SYS-1 to POP-1, controlling the differential transcription of Wnt target genes between daughters of an asymmetric cell division. Because our genetic data indicate an antagonism between LRP-2 and LIN-17 similar to that between CAM-1 and VANG-1 and LIN-17 (Minor and Sternberg, 2019), we wanted to determine if LRP-2 can control the asymmetric localization of SYS-1 between the daughter cells of P7.p during anaphase of the first cell division. The initial establishment of vulval polarity can be observed through the localization of VENUS::SYS-1 (VNS::SYS-1), localized in a high (P7.pa)/low (P7.pp) pattern in the wild-type worm, reciprocal to the localization of POP-1/TCF (Phillips et al., 2007; Green et al., 2008). It was previously reported (Green et al. 2008) that VNS::SYS-1 asymmetry in P7.p daughter cells is often lost in lin-17(n671) and lin-18(e620) mutants. These mutants display two aberrant patterns of VNS::SYS-1 localization as well as the wild-type pattern, though less frequently. The two deviant localization patterns include one in which both P7.pa and P7.pp express equal amounts of VNS::SYS-1 and a reversed VNS::SYS-1 pattern in which P7.pp is enriched with VNS::SYS-1. By observing VNS::SYS-1 localization in a lin-17(n671); lrp-2(gk272) background we see that the aberrant localization of SYS-1 is suppressed to a similar degree to that of lin-17(n671); cam-1(gm122) and lin-17(n671); vang-1(ok1142). This observation confirms LRP-2 controls vulval cell polarity by antagonizing LIN-17 in a similar fashion to CAM-1 and VANG-1, and that the effect of LRP-2 is at the level of P7.p rather than its progeny

Genetics of intercellular signalling in C. elegans

Cell-cell interactions play a significant role in controlling cell fate during development of the nematode Caenorhabditis elegans. It has been found that two genes, glp-1 and lin-12, are required for many of these decisions. glp-1 is required for induction of mitotic proliferation in the germline by the somatic distal tip cell and for induction of the anterior pharynx early in embryogenesis. lin-12 is required for the interactions between cells of equivalent developmental potential, which allow them to take on different fates. Comparison of these two genes on a molecular level indicates that they are similar in sequence and organization, suggesting that the mechanisms of these two different sets of cell-cell interactions are similar

Controlling occupational cancers in Australia

Lin Fritschi, Renae C Fernandez, Deborah A Vallance, Terry J Slevin, Alison Reid, Timothy R Driscoll, Deborah C Glas

Lin Lin Lin v. Atty Gen USA

Agenc

Exploring the EGF/Ras and Notch/DSL Signaling Pathways in Members of the Caenorhabditis Genus

Many pathways exist in animal systems for cells to communicate and facilitate proper cell division; two such pathways are the EGF/Ras pathway and the Notch/DSL pathway, both of which are crucial to proper vulval development in nematodes of the Caenorhabditis genus. These pathways are conserved in humans and many other species as well, making them viable topics for research. This project seeks to study these pathways, especially the diversity of each path, and how the they work together to allow successful vulvagenesis. To examine pathway diversity, evolutionary trees (generated by TreeFam.org) for genes vital to each pathway were collected and compared to each other. This analysis revealed more gene duplication in the Notch pathway among members of the Caenorhabditis genus, while relatively little gene duplication exists in the EGF/Ras pathway. This suggests that the Notch pathway is more flexible, and allows more evolutionary diversity. To test this prediction, I am comparing the function of these pathways between Caenorhabditis elegans and Caenorhabditis briggsae. For studying the EGF/Ras pathway, I am examining the gene lin-3/EGF. Over expression of lin-3/EGF in C. elegans leads to the inappropriate division of epithelial cells. My data show overexpression of C. briggsae lin-3 causes a similar phenotype in both C. elegans and C. briggsae worms. Additionally, during this project new splice variants of the lin-3 gene were discovered in C. elegans, C. briggsae, and C. remanei. Notably, several of these variants either include or exclude a possible processing site. The tools developed in this project will be valuable assets for further studying these critical signaling pathways in various animal systems.Undergraduate Research Scholarship - College of Arts and SciencesPelotonia FellowshipNo embargoAcademic Major: Zoolog

Deformable Part-based Fully Convolutional Network for Object Detection

Existing region-based object detectors are limited to regions with fixed box geometry to represent objects, even if those are highly non-rectangular. In this paper we introduce DP-FCN, a deep model for object detection which explicitly adapts to shapes of objects with deformable parts. Without additional annotations, it learns to focus on discriminative elements and to align them, and simultaneously brings more invariance for classification and geometric information to refine localization. DP-FCN is composed of three main modules: a Fully Convolutional Network to efficiently maintain spatial resolution, a deformable part-based RoI pooling layer to optimize positions of parts and build invariance, and a deformation-aware localization module explicitly exploiting displacements of parts to improve accuracy of bounding box regression. We experimentally validate our model and show significant gains. DP-FCN achieves state-of-the-art performances of 83.1% and 80.9% on PASCAL VOC 2007 and 2012 with VOC data only.Comment: Accepted to BMVC 2017 (oral

Ming-Hui Lin, flute and Ayako Yoda, piano and harpsichord, April 25, 2015

This is the concert program of the Ming-Hui Lin, flute and Ayako Yoda, piano and harpsichord performance on Saturday, April 25, 2015 at 8:30 p.m., at the Marshall Room, 855 Commonwealth Avenue. Works performed were Sonata in C major for Flute and Basso Continuo, BWV 1033 by Johann Sebastian Bach, Sonata for Flute and Piano, No. 3 by Philippe Gaubert, Sonatina for Flute and Piano by Eldin Burton, Syrinx for Flute solo by Claude Debussy, and Introduction and Variations on "Trockne Blumen" in E minor for Flute and Piano, D802 by Franz Schubert. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund