Theses and Dissertations

Issuing Body

Mississippi State University


Ma, Din-Pow

Committee Member

Jenkins, Johnie N.

Committee Member

Saha, Sukumar

Committee Member

Peng, Zhaohua

Committee Member

Li, Jiaxu

Date of Degree


Document Type

Graduate Thesis - Open Access



Degree Name

Master of Science


College of Agriculture and Life Sciences


Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology


The ubiquitin-proteasome proteolysis pathway is responsible for the degradation of abnormal and short-lived proteins to regulate many important biochemical activities in eukaryotes. By employing affymetrix microarray analysis, we have identified a novel ubiquitin ligase E3 gene GhRING2 that is expressed differentially between two G. hirsutum lines - Texas Marker-1 and Chromosome Substitution Line CS-B25. The complete GhRING2 gene sequence was obtained by genomic and cDNA walking. The expression of GhRING2 in cotton fiber is developmentally regulated, suggesting that the ubiquitin-proteasome pathway may regulate cotton fiber growth and development. Using a yeast two-hybrid assay GhRING2 was found to interact with a PROTODERMAL FACTOR1 (GhPDF1) protein. GhPDF1 is expressed preferentially in immature ovules and fiber initials and the gene has been suggested to play a role in cell fate determination and fiber development. Pull down and plasmid swap assays were employed to confirm this interaction.