Undergraduate Honors Thesis Projects

Date of Award

2016

Document Type

Honors Paper

Degree Name

Biochemistry and Molecular Biology-BS

Department

Biology & Earth Science

Advisor

Dr. Jennifer Bennett

First Committee Member

Dr. Jennifer Bennett

Second Committee Member

Dr. John Tansey

Third Committee Member

Dr. Jonathan DeCoster

Keywords

cyclic-di-GMP, streptomyces, streptomyces coelicolor, gene expression, RNA sequencing

Subject Categories

Bacteriology | Biology | Life Sciences

Abstract

The second messenger molecule cyclic dimeric GMP (c-di-GMP) regulates a myriad of processes in gram-negative bacteria. However, less is known about the roles it plays in gram-positive bacteria. Differential gene expression in three strains of the gram-positive bacterium, Streptomyces coelicolor, is being studied using RNA sequencing and Real Time PCR to gain insight into c-di-GMP signaling. The rmdA rmdB (regulator of morphology and development) double mutant was compared to the wild type strain known as MT1110. The rmdA and rmdB genes are needed for the formation of aerial mycelium, an important step in the life cycle of Streptomyces coelicolor (Hull et al., 2012). A diguanylate cyclase mutant was also compared to the wild type strain of S. coelicolor. The RNA sequencing experiment revealed that 3,151 genes are differentially expressed in the phosphodiesterase double mutant and 1,341 genes are differentially expressed in the diguanylate cyclase mutant when both mutants are compared to the wild type strain of S. coelicolor. Both known and uncharacterized genes were found in the data to be differentially expressed. Genes of interest for future study were also identified. In particular, the chaplin genes were found to be expressed at significantly lower levels in the phosphodiesterase double mutant as predicted prior to completing the experiment. The chaplins are critical protein players in the formation of aerial hyphae. Real Time PCR experiments are currently being conducted to confirm the results obtained using RNA sequencing.

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