Genetics and Genomics Commons^™

Analysis Of Argonaute-Small Rna-Transcription Factor Circuits Controlling Leaf Development, John Steen Hoyer

Arts & Sciences Electronic Theses and Dissertations

Experimental studies of plant development have yielded many insights into gene regulation, revealing interactions between core transcriptional and post-transcriptional regulatory pathways present in all land plants. This work describes a direct connection between the three main small RNA-transcription factor circuits controlling leaf shape dynamics in the reference plant Arabidopsis thaliana. We used a high-throughput yeast 1-hybrid platform to identify factors directly binding the promoter of the highly specialized ARGONAUTE7 silencing factor. Two groups of developmentally significant microRNA-targeted transcription factors were the clearest hits from these screens, but transgenic complementation analysis indicated that their binding sites make only a small contribution …

Mechanism Of Gene Regulation By Coding Polya Tracks, Laura Lea Arthur

Arts & Sciences Electronic Theses and Dissertations

Regulation of gene expression is essential for cellular development and survival. The great variety and complexity of regulatory mechanisms underscores this fact. Messenger RNA stability and translational efficiency are often key determinants of gene expression. mRNA surveillance pathways, discovered for their role in degradation of aberrant mRNA, are now known to be instrumental in the regulation of physiologically correct mRNA stability. Thus, the study of cis elements in a transcript that can induce mRNA surveillance pathways has become an area of particular interest.

Here I report on the mechanism of gene regulation by coding polyA tracks, defined as a sequence …

Factors That Contribute To De Novo Protein Misfolding And Prion Formation In Saccharomyces Cerevisiae, Kathryn Morgan Keefer

Arts & Sciences Electronic Theses and Dissertations

Protein misfolding is a common phenomenon that can have severe consequences on cellular and organismal health. Despite this, the causes of protein misfolding remain poorly understood. Prions are a class of proteins that, when misfolded, can convert other molecules into a heritable, non-native conformation. The yeast Saccharomyces cerevisiae naturally harbors several diverse prion-forming proteins; thus, it is an ideal model with which to investigate the factors that influence misfolding and aggregation.This thesis utilizes the yeast prions [PSI+] and [RNQ+] to investigate two distinct steps of the protein misfolding pathway: interactions with chaperones and their cofactors, and heterologous templating by other …

Genetic And Genomic Dissections Of Myelinating Glial Cell Development, Breanne Leigh Harty

Arts & Sciences Electronic Theses and Dissertations

Myelin is a multilamellar sheath made by specialized glial cells that iteratively spiral and compact their plasma membranes around axon segments. In vertebrate nervous systems, myelination facilitates rapid action propagation and provides trophic support critical for neuronal survival. In the central nervous system (CNS), oligodendrocytes (OLs) extend many processes to simultaneously ensheath multiple axons, while in the peripheral nervous system (PNS), myelinating Schwann cells (SCs) pair 1:1 with a single axon segment. Elaboration of the myelin sheath is one of the most exquisite and complex examples of massive coordinated cellular shape changes in the vertebrate nervous system. Furthermore, the importance …