Qi Luo

Document Type

Thesis - University Access Only

Award Date

1997

Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology

Abstract

Previous studies have shown that CDP-choline: diacylglycerol cholinephosphotransferase (CPT) is a key component of membrane lipid synthesis in vegetative tissues and triglyceride synthesis in developing soybean seeds. Enzyme levels are known to be regulated developmentally, environmentally, and hormonally. The enzyme is present at a low level in extracts from seeds during late R4. The activity increases until RS then decreases to undetectable levels before the end of seed fill. Tissue specific regulation of these events was investigated by analyzing the expression of CPT rnRNAin seeds from mid-R4 through mid-RS stages using fluorescence in situ hybridization (FISH). Tissue hybridizations were conducted using a 400 bp fragment from the 5' coding region of CPT rnRNA. Sense and antisense riboprobes were made by in vitro transcription using fluorescein-UTP. Sections were counter stained with propidium iodide. The antisense probe revealed expression of CPT in all samples, while the sense probe showed no detectable signal. In mid-R4 seeds, detectable CPT expression was confined to the outer integument. Late-R4 seeds showed detectable expression in all seed tissues except the aleurone layer. By mid-RS high level expression was confined to the cotyledons, while lower level expression could be detected in the inner integument. Temperature treated late-R4 seeds showed that CPT mRNA accumulated at cold temperature, but was repressed at warm temperature. Image analysis of mid-RS seeds showed that the hybridized mRNAs were localized in the cytoplasm.

Library of Congress Subject Headings

Phosphotransferases

Soybean -- Seeds

Fatty acids -- Synthesis

Format

application/pdf

Number of Pages

90

Publisher

South Dakota State University

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