No description available.

DRMT4 (Drosophila Arginine MethylTransferase 4) is an arginine methyltransferase in Drosophila (Boulanger et al. 2004). It shows the highest identities with mammalian PRMT4/CARM1 (Protein Arginine MethylTransferase 4) (59% identity, 75% similarity). HPLC analysis demonstrated that DRMT4 belongs to the type I class of methyltransferases (Boulanger et al. 2004), meaning that DRMT4 catalyzes asymmetrical dimethylarginine formation. A polyclonal antibody against DRMT4 was generated and used to study DRMT4 expression using western blots and immunostainings. In order to study DRMT4 function in Drosophila using genetic methods, we created three kinds of DRMT4 transgenes: a genomic DRMT4 under its own control, a genomic DRMT4-GFP fusion gene and a cDNA DRMT4 under UAS control. We investigated DRMT4 localization in wild type flies using the DRMT4-GFP transgenic line and immunostaining.

Oocyte loss and meiotic prophase progression was studied in XY sex-reversed and XO female mice, two mouse models that lack pairing between their sex chromosomes. An arrest at the pachytene stage of meiosis was not observed, nor was a significant loss of oocytes at this stage compared to normal XX control mice. Thus, it was concluded that a pairing checkpoint either does not exist in oocytes or is not as stringent as the one observed in males. / The effect of mutating the pro-apoptotic Bax molecule was studied at three distinct ages corresponding to the time when female germ cells are premeiotic, in meiotic prophase, and arrested in dictyotene. Although it appeared that more germ cells were retained in the Bax homozygous mutant compared to the wild-type and heterozygous mice at 18.5 dpc, by 24.5 dpc all of the mice possessed similar numbers of germ cells. These results indicate a role for Bax in germ cell death but also support the idea that an alternative pathway can compensate for the elimination of this molecule.

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The studies submitted for this thesis encompass two broad areas of interest. The first is the role of extracellular matrix during folliculogenesis, including ovulation and corpus luteum formation. The observations made were extended in a second series of studies investigating matrix and other parameters of morphologically distinct follicles. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1274421 / Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2007

Thesis (Ph. D.)--University of Wisconsin--Madison, 1926. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 49-52).

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [86]-93).

Most species of freshwater cyclopoid copepods follow a conventional course of DNA replication during gametogenesis, but certain species regularly undergo chromatin diminution during early embryogenesis, a process that is accompanied by the exclusion of large amounts of heterochromatic DNA from progenitor somatic cells and selective retention of this DNA by primordial germ cells after their segregation from the soma. We have used scanning microdensitometry and image analysis cytometry of individual Feulgen-stained nuclei to determine the DNA levels of individual somatic cell nuclei, oocytes, spermatocytes, and sperm for seven species, including Acanthocyclops brevispinosus, Acanthocyclops vernalis, Ectocyclops phaleratus, Eucyclops agilis, Eucyclops ensifer, Macrocyclops albidus, and Thermocyclops decipiens. The oocyte nuclei of these species have twice the DNA content of their diploid somatic cell nuclei. In specimens of Cyclops strenuus, Mesocyclops edax, Mesocyclops longisetus, Mesocyclops longisetus curvatus, and Metacyclops mendocinus, marked increases in DNA levels were noted in both female and male germ cells before meiosis. The appearance of enlarged nuclei with densely stained chromocenters is a distinguishing feature of oocytes and spermatocytes of cyclopoid species that exhibit excessive accumulations of DNA during gametogenesis and subsequently undergo chromatin diminution. The net increase in DNA content of the prediminution nuclei is 6-10 times the DNA level of their somatic cell nuclei and is largely attributable to increases in the amount of DNA associated with their heterochromatic chromocenters. The identification of a morphologically distinctive type of germ cell and its dramatic accumulation of large amounts of DNA before meiosis are discussed in terms of the selective elimination of heterochromatin during early cleavage stages in these cyclopoid species.

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No description available.