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Full-Text Articles in Medicine and Health Sciences

Role Of Recurrent Hydrophobic Residues In Catalyzing Helix Formation By T Cell-Presented Peptides: A Thesis, Shan Lu Dec 1990

Role Of Recurrent Hydrophobic Residues In Catalyzing Helix Formation By T Cell-Presented Peptides: A Thesis, Shan Lu

GSBS Dissertations and Theses

The overall objective of this study was to understand the mechanisms that control antigen processing and binding of peptides to major histocompatibility complex (MHC) molecules. Towards this goal I investigated (a) the structural features of T cell-presented peptides with a focus on the role of recurrent hydrophobic residues in catalysis of helix formation by these peptides and (b) the biochemical events that determine the fates of the invariant chain molecule (Ii) in its various post-translational processing pathways.

In the structural studies, I tested the hypothesis that the recurrence of hydrophobic amino acids in a polypeptide at positions falling in an ...


Functional And Structural Characterization Of A Human H4 Histone Gene Promoter: A Thesis, Kenneth Lynn Wright Nov 1990

Functional And Structural Characterization Of A Human H4 Histone Gene Promoter: A Thesis, Kenneth Lynn Wright

GSBS Dissertations and Theses

Expression of the cell cycle dependent FO10S human H4 histone gene is regulated at both the transcriptional and post-transcriptional levels. We have investigated the 5' promoter elements mediating the transcriptional aspects of its regulation. A detailed in vivo and in vitro transcriptional analysis of promoter deletion mutants from this gene has identified three positive regulatory elements and two potentially negative regulatory elements within the first 1000 base pairs upstream of the transcription initiation site. In addition, the minimal promoter located within the first 70 base pairs is required for accurate transcription initiation and contains one of two in vivo identified ...


Regulation Of Β-Adrenergic-Induced Protein Phosphorylation In The Myocardium: A Dissertation, Edward E. George Oct 1990

Regulation Of Β-Adrenergic-Induced Protein Phosphorylation In The Myocardium: A Dissertation, Edward E. George

GSBS Dissertations and Theses

The purpose of this investigation was to examine selected biochemical mechanisms known to influence contractility and energy metabolism in the myocardium, with particular emphasis placed on the regulatory role of protein phosphorylation in the ventricular myocardium. The investigation was conducted in three phases; initially the cardiac contraction cycle was examined to determine whether reported fluctuations in myocardial cAMP levels were associated with other biochemical events known to be cAMP-dependent. The second phase involved the determination of specific kinase activities and endogenous substrates in a highly purified cardiac sarcolemmal preparation. In the final phase, ventricular myocytes were utilized to examine the ...


The Structure, Function, And Regulation Of Insulin-Like Growth Factor Ii/Mannose 6-Phosphate Receptor Forms: A Thesis, Kevin B. Clairmont Oct 1990

The Structure, Function, And Regulation Of Insulin-Like Growth Factor Ii/Mannose 6-Phosphate Receptor Forms: A Thesis, Kevin B. Clairmont

GSBS Dissertations and Theses

In mammals a single receptor protein binds both insulin-like growth factor II (IGF-II) and mannose 6-phosphate (Man 6-P) containing ligands, most notably lysosomal enzymes. However, in chick embryo fibroblasts IGF-II binds predominantly to a type 1 IGF receptor, and no IGF-II/Man 6-P receptor has been identified in this species. In order to determine if chickens possess an IGF-II/Man 6-P receptor, an affinity resin (pentamannosyl 6-phosphate (PMP) Sepharose) was used to purify receptors from chicken membrane extracts by their ability to bind mannose 6-phosphate. Then 125I-IGF-II was used to evaluate their ability to bind IGF-II. These experiments demonstrate ...


Mutually Dependent Elements In The Neurotensin/Neuromedin N Gene Promoter Integrate Multiple Environmental Stimuli In Pc12 Cells: A Thesis, Edward H. Kislauskis Jun 1990

Mutually Dependent Elements In The Neurotensin/Neuromedin N Gene Promoter Integrate Multiple Environmental Stimuli In Pc12 Cells: A Thesis, Edward H. Kislauskis

GSBS Dissertations and Theses

This thesis examines the structure and regulated expression of the gene encoding the neuroendocrine peptides neurotensin and neuromedin N (NT/N gene). Previous studies have shown that expression of NT/N mRNA and NT peptide in PC12 cells are strictly dependent on simultaneous exposure to combinations of nerve growth factor (NGF), glucocorticoids, activators of adenylate cyclase, and lithium ion. My objective was to characterize the cis-regulatory DNA sequences involved in regulated expression of this gene.

The initial focus of this study was an analysis of the structure, tissue-specific expression, and exon evolution of the rat NT/N gene. Nucleotide sequence ...


The Stimulation Of Luteinizing Hormone Secretion From Anterior Pituitary Cells In Culture By Substance P: A Dissertation, Maureen Shamgochian May 1990

The Stimulation Of Luteinizing Hormone Secretion From Anterior Pituitary Cells In Culture By Substance P: A Dissertation, Maureen Shamgochian

GSBS Dissertations and Theses

The observations that substance P (SP) is localized in the anterior pituitary gland (AP) and is regulated by the hormonal status of the animal, as well as the demonstration of SP binding sites in the AP, have led to the idea that SP may participate in the regulation of AP function. Numerous and sometimes contradictory reports of SP effects on AP hormone secretion, particularly on luteinizing hormone (LH), left the question of whether SP acts directly at the level of the AP to regulate LH secretion still unanswered. To investigate a possible physiological function of SP in the AP, the ...


Genetic Analysis Of The Saccharomyces Cerevisiae Pheromone Response Pathway: A Thesis, Dmitry B. Blinder May 1990

Genetic Analysis Of The Saccharomyces Cerevisiae Pheromone Response Pathway: A Thesis, Dmitry B. Blinder

GSBS Dissertations and Theses

The cell division of Saccharomyces cerevisiae is controlled by the action of pheromones at the G1 phase of the cell cycle. A general method was developed for the isolation of constitutive mutants in the pheromone response pathway. Recessive alleles of the SCG1 gene (encoding the α subunit of a G protein) were isolated as well as a dominant mutation in the STE4 gene (encoding the β subunit of a G protein). Analysis of double mutants suggested that the STE4 gene product functions after the SCG1 product but before the STE5 gene product. Double mutants carrying either scg1 or STE4Hp1 ...