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Full-Text Articles in Molecular Biology

The Dlk1-Meg3 Locus In Malignant Cells Of Proposed Primordial Germ Cell Origins., Zachariah Payne Sellers Aug 2017

The Dlk1-Meg3 Locus In Malignant Cells Of Proposed Primordial Germ Cell Origins., Zachariah Payne Sellers

Electronic Theses and Dissertations

Primordial germ cells (PGCs) are hypothesized to deposit hematopoietic stem cells (HSCs) along their migration route through the embryo during the early stages of embryogenesis. PGCs also undergo global chromatin remodeling, including the erasure and reestablishment of genomic imprints, during this migration. While PGCs do not spontaneously form teratomas, their malignant development into germ cell tumors (GCTs) in vivo is often accompanied by the retention of hypomethylation at the IGF2-H19 imprinting control differentially methylated region (DMR). Previous studies in bimaternal embryos determined that proper genomic imprinting at two paternally imprinted loci was necessary for their growth and development: Igf2-H19 and ...


Regulation Of Chromosome Segregation In Drosophila Meiosis, Zhi Hao Guo Jan 2014

Regulation Of Chromosome Segregation In Drosophila Meiosis, Zhi Hao Guo

Electronic Theses and Dissertations

Sister-chromatid cohesion is maintained by Cohesin complex. Separase releases the cohesion through the cleavage of the kleisin subunit of Cohesin complex. Separase is regulated by its inhibitor, Securin/Pim. These processes are well studied in mitosis but little is known for meiosis. I found that Separase is required for the proper separation of homologous chromosomes and sister chromatids in Drosophila meiosis. Its function is inhibited by Securin/Pim during the process. I showed that the common kleisin subunit, Rad21, is not likely to be the meiotic target of Separase and that Rad21 and another common Cohesin component, SMC3/CAP, does ...


A Temperature-Sensitive Mutant Of Escherichia Coli Affected In The Alpha Subunit Of Rna Polymerase, Majid Mehrpouyan Dec 1990

A Temperature-Sensitive Mutant Of Escherichia Coli Affected In The Alpha Subunit Of Rna Polymerase, Majid Mehrpouyan

Electronic Theses and Dissertations

A temperature-sensitive mutant of Escherichia coli affected in the alpha subunit of RNA polymerase has been investigated. Gene mapping and complementation experiments placed the mutation to temperature-sensitivity within the alpha operon at 72 min on the bacterial chromosome. The rate of RNA synthesis in vivo and the accumulation of ribosomal RNA were significantly reduced in the mutant at 44$\sp\circ$C. The thermostability at 44$\sp\circ$C of the purified holoenzyme from mutant cells was about 20% of that of the normal enzyme. Assays with T7 DNA as a template showed that the fraction of active enzyme competent ...