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Full-Text Articles in Medicine and Health Sciences

Role Of Map Kinases In The Induction Of Heme Oxygenase-1 By Arsenite: Studies In Chicken Hepatoma Cells: A Dissertation, Kimberly Kirstin Elbirt May 1998

Role Of Map Kinases In The Induction Of Heme Oxygenase-1 By Arsenite: Studies In Chicken Hepatoma Cells: A Dissertation, Kimberly Kirstin Elbirt

GSBS Dissertations and Theses

The chicken hepatoma cell line, LMH, was evaluated with respect to its usefulness for studies of the regulation of heme metabolism. Levels of δ-aminolevulinate synthase mRNA arid accumulation of porphyrins were used to evaluate the heme biosynthetic pathway. Regulation of heme oxygenase-1 by known inducers was used as a measure of heme degradation. The induction of heme oxygenase-1 by sodium arsenite was characterized. AP-1 transcription factor elements and MAP kinase signal transduction pathways that modulate expression of endogenous heme oxygenase-1 and transfected heme oxygenase-1 reporter gene constructs in response to arsenite were delineated.

In initial studies, the drug glutethimide was ...


Structural Association Of Xist Rna With Inactive Chromosomes In Somatic Cells : A Key Step In The Process That Establishes And Faithfully Maintains X-Inactivation, Christine Moulton Clemson May 1998

Structural Association Of Xist Rna With Inactive Chromosomes In Somatic Cells : A Key Step In The Process That Establishes And Faithfully Maintains X-Inactivation, Christine Moulton Clemson

GSBS Dissertations and Theses

The XIST gene is implicated in X-chromosome inactivation, yet the RNA contains no apparent open reading frame. An accumulation of XIST RNA is observed near its site of transcription, the inactive X chromosome (Xi). A series of molecular cytogenetic studies comparing properties of XIST RNA to other protein coding RNAs, support a critical distinction for XIST RNA; XIST RNA does not concentrate at Xi simply because it is transcribed and processed there. Most notably, morphometric and 3-D analysis reveals that XIST RNA and Xi are coincident in 2-D and 3-D space; hence the XIST RNA essentially paints Xi. Several results ...


Transcriptional Regulation Of A Human H4 Histone Gene Is Mediated By Multiple Elements Interacting With Similar Transcription Factors: A Dissertation, Thomas J. Last May 1998

Transcriptional Regulation Of A Human H4 Histone Gene Is Mediated By Multiple Elements Interacting With Similar Transcription Factors: A Dissertation, Thomas J. Last

GSBS Dissertations and Theses

Synthesis of histone proteins occurs largely during the S phase of the cell cycle and coincides with DNA replication to provide adequate amounts of histones necessary to properly package newly replicated DNA. Controlling transcription from cell cycle dependent and proliferation specific genes, including histone H4, is an important level of regulation in the overall governance of the cell growth process. Coordination of histone gene transcription results from the cumulative effects of cell signaling pathways, dynamic chromatin structure and multiple transcription factor interactions. The research of this dissertation focused on the characterization and identification of transcription factors interacting on the human ...


Analysis Of The Mechanism Of Ras Activation: Mapping Of Important Functional Domains Of The Son Of Sevenless Protein, Linda Sue Mccollam-Guilani Feb 1998

Analysis Of The Mechanism Of Ras Activation: Mapping Of Important Functional Domains Of The Son Of Sevenless Protein, Linda Sue Mccollam-Guilani

GSBS Dissertations and Theses

The questions outlined in this thesis dissertation were proposed in order to provide insight regarding the mechanism by which the Drosophila Son of sevenless (dSOS) protein activates Ras. Ras proteins are GTP-binding proteins which bind guanine nucleotides very tightly and cycle between the inactive GDP-bound state and the active GTP-bound state. To address the mechanism by which the dSOS proteins activates Ras, a structure-function analysis of the dSOS protein was performed using truncation and deletion mutants of dSOS. In vivo Ras activation experiments using transiently transfected cells revealed that the NH2-terminal domain of dSOS is required in order ...


Cloning And Characterization Of Dynamitin, The 50 Kda Subunit Of Dynactin: A Study Of Dynactin And Cytoplasmic Dynein Function In Vertebrates, Christophe De Jesus Echeverri Jan 1998

Cloning And Characterization Of Dynamitin, The 50 Kda Subunit Of Dynactin: A Study Of Dynactin And Cytoplasmic Dynein Function In Vertebrates, Christophe De Jesus Echeverri

GSBS Dissertations and Theses

Dynactin is a multi-subunit complex which was initially identified in 1991 as an activator of cytoplasmic dynein-driven microtubule-based organelle motility in vitro. Although genetic studies also supported the involvement of both complexes in the same functional pathways in yeast, filamentous fungi, and Drosophila, none of these findings yielded significant insights into dynactin's mechanism of action. The full range of cytoplasmic dynein functions in vertebrate cells has also remained poorly understood, due, in large part, to the lack of a specific method of inhibition. The present thesis work was designed to investigate these issues through a study of the 50 ...


Genetic And Biochemical Analysis Of The Activation Mechanism Of The Saccharomyces Cerevisiae Pheromone Receptor, Gul H. Bukusoglu Jan 1998

Genetic And Biochemical Analysis Of The Activation Mechanism Of The Saccharomyces Cerevisiae Pheromone Receptor, Gul H. Bukusoglu

GSBS Dissertations and Theses

Activation mechanism of the α-factor pheromone receptor of Saccharomyces cerevisiae was analyzed using biochemical and genetic techniques. An in vitro partial proteolysis assay was developed to determine the conformational change of the receptor that occurs upon binding of agonist. The activation specific cleavages were established by comparing cleavage products with antagonist versus agonist occupied receptor. Of the changes in peptide pattern that were revealed by trypsinization, the fragment resulting from the exposure of the third loop to the protease was found to be agonist specific and to be G-protein independent. A low-affinity binding receptor mutant was isolated which failed to ...


Analysis Of Taf Ii Function In The Yeast Saccharomyces Cerevisiae, Lynne Marie Apone Jan 1998

Analysis Of Taf Ii Function In The Yeast Saccharomyces Cerevisiae, Lynne Marie Apone

GSBS Dissertations and Theses

Transcription by RNA polymerase II is a highly regulated process requiring a number of general and promoter specific transcription factors. Although many of the factors involved in the transcription reaction are known, exactly how they function to stimulate or repress transcription is not well understood. Central to understanding gene regulation is understanding the mechanism by which promoter specific transcription activators (activators) stimulate transcription.

A group of factors called coactivators have been shown to be required for activator function in vitro. The best characterized coactivators to date are members of the TFIID complex. TFIID is a multisubunit complex composed of the ...