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Efficient Gene Transfer In C.Elegans: Extrachromosomal Maintenance And Integration Of Transforming Sequences, Craig Mello, James Cramer, Dan Stinchcomb, Victor Ambros
Efficient Gene Transfer In C.Elegans: Extrachromosomal Maintenance And Integration Of Transforming Sequences, Craig Mello, James Cramer, Dan Stinchcomb, Victor Ambros
Victor R. Ambros
We describe a dominant behavioral marker, rol-6(su-1006), and an efficient microinjection procedure which facilitate the recovery of Caenorhabditis elegans transformants. We use these tools to study the mechanism of C.elegans DNA transformation. By injecting mixtures of genetically marked DNA molecules, we show that large extrachromosomal arrays assemble directly from the injected molecules and that homologous recombination drives array assembly. Appropriately placed double-strand breaks stimulated homologous recombination during array formation. Our data indicate that the size of the assembled transgenic structures determines whether or not they will be maintained extrachromosomally or lost. We show that low copy number extrachromosomal transformation can …
Alternative Temporal Control Systems For Hypodermal Cell Differentiation In Caenorhabditis Elegans, Zhongchi Liu, Victor Ambros
Alternative Temporal Control Systems For Hypodermal Cell Differentiation In Caenorhabditis Elegans, Zhongchi Liu, Victor Ambros
Victor R. Ambros
Beginning of article: In certain multicellular organisms, genetic regulatory systems that specify the timing of cell division, differentiation and morpho-genesis must accommodate environmental and physiological contingencies that perturb or arrest development. For example, Caenorhabditis elegans can either develop continuously through four larval stages (L1–L4) or arrest indefinitely as a 'dauer larva' at the second larval (L2) moult, and later resume L3 and L4 development. At the larva-to-adult (L4) moult of both con-tinuous and 'post-dauer' development, hypodermal cells switch (the 'L/A switch') from a proliferating state to the terminally differentiated state. Four temporal regulators, lin-4, lin-14, lin-28 and lin-29, have been …
Molecular Cloning Of Lin-29, A Heterochronic Gene Required For The Differentiation Of Hypodermal Cells And The Cessation Of Molting In C.Elegans, A. Papp, A. Rougvie, Victor Ambros
Molecular Cloning Of Lin-29, A Heterochronic Gene Required For The Differentiation Of Hypodermal Cells And The Cessation Of Molting In C.Elegans, A. Papp, A. Rougvie, Victor Ambros
Victor R. Ambros
The lin-29 gene product of C.elegans activates a temporal developmental switch for hypodermal cells. Loss-of-function lin-29 mutations result in worms that fail to execute a stage-specific pattern of hypodermal differentiation that includes exist from the cell cycle, repression of larval cuticle genes, activation of adult cuticle genes, and the cessation of molting. Combined genetic and physical mapping of restriction fragment length polymorphisms (RFLPs) was used to identify the lin-29 locus. A probe from the insertion site of a Tc1 (maP1), closely linked and to the left of lin-29 on the genetic map, was used to identify a large set of …