Analysis of DNA methylation in the growth and development of the Early Alaska pea (Pisum sativum)

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Authors
Neeb, Laura A.
Advisor
Allamong, Betty D.
Issue Date
1986
Keyword
Degree
Thesis (M.S.)--Ball State University, 1986.
Department
Other Identifiers
Abstract

The methylation of specific gene sites is thought to play a controlling role in gene expression in microorganisms, higher plants, and animals. The relationship between methylation of DNA and gene expression has been well documented in microorganisms and animals; however, the regulatory role of methylation in higher plants has remained relatively unresearched. The focus of this study was to investigate fluctuations in DNA methylation during the early development of the pea (Piston sativum).Pea seeds were grown for 12 days (in Vermiculite) in a growth chamber. Duplicate samples of 30 seedlings were harvested daily. The samples were pulse-labeled with S-adenosyl-L-methionine-C3H3 for 10 hr. The labeled methyl group was allowed to be incorporated into the DNA as the samples continued to grow and differentiate. The methyltransferase action was stopped by freezing.DNA was then extracted, purified, and quantitated. Included in the analysis was the quantitation of RNA. The methylation was quantitated through liquid scintillation spectroscopy.Analysis of the fluctuations in the methylation of nucleic acids, over the growth period of seedling differentiation, was done. Methylated DNA was quantitated based on a comparison of radioactivity in extracted DNA minus the radioactivity' attributed to the extracted RNA. Fluctuations in methylation of DNA correlated to the growth patterns observed in the pea seedlings. This study supported the current hypothesis that differentiation in plants may be the result of methylated DNA masking the expression of selective genes. The results suggested that methyl group alterations on RNA follow the DNA pattern and may also play a significant role in gene expression.Ball State UniversityMuncie, IN 47306

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