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

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

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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

\u3cem\u3eTetrahymena thermophila\u3c/em\u3e Lack a Homologue of the Caenorhabditis Elegans Lin-4 miRNA

The netrin family of proteins was first discovered because of their role in axonal guidance during development. Netrin homologues are important developmental signals in organisms ranging from vertebrates to the nematode, Caenorhabditis elegans, and netrin-like proteins have even been found in the ciliated protozoan, Tetrahymena thermophila. Since the lin-4 miRNA regulates netrin signaling in C. elegans, we hypothesized that a lin-4 homologue might exists in Tetrahymena thermophila. In order to test this hypothesis, we purified total miRNA from T. thermophila, used this miRNA to make cDNA, then used RT-PCR to quantitate the amount of lin-4 specific cDNA we obtained. Our sample was positive for total cDNA, but not for the lin-4 cDNA specifically, suggesting that this miRNA may not have a homologue in Tetrahymena