Characterization of arcelin-1 expression and effect of the arcelin-1 locus on phaseolin expression in Phaseolus vulgaris and transgenic tobacco /
| Main Author: | |
|---|---|
| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
|
| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | The overall objective of the research presented here was to investigate the molecular basis for coordinate expression of the phaseolin gene family by examining phaseolin expression in plants in which the expression of all phaseolin genes is reduced. Because the coordinate suppression of phaseolin gene expression occurs only in plants which express arcelin, characterization of arcelin expression at the molecular level was undertaken. SG3 seeds express high levels of arcelin (arc+ trait), a seed -specific, developmentally regulated protein closely related to bean lectin, and only low levels of phaseolin, which is norm ally the major seed storage protein in beans. A genomic library constructed from SG3 DNA was screened with an arcelin PCR product also obtained from SG3 genomic DNA. Of six clones obtained, the deduced amino acid sequence of one (Z5, 4.5 kb) matched the N -terminal sequence obtained from microsequencing of the mature arcelin protein. The Z5 clone was used to probe genomic blots of arc+ and arc- wild bean lines, the cultivated variety 'Sanilac' (arc-), and SG3 (arc+). Although the lectin profiles for wild and cultivated lines were disparate, the lectin profiles for arc+ lines were nearly identical, strongly suggesting linkage of arcelin and lectin genes. Novel phaseolin sequences were present in arc+ lines. Arcelin m RNA was first seen 12 days postanthesis, and the presence of arcelin correlated with a decreased phaseolin m RNA level. Reconstruction analysis revealed 35 copies of the 4.5 kb arcelin gene in arc+ lines, and the total gene copy number of arcelin is approximately 70. Although the 5' sequences of arcelin and phaseolin genes show little overall sequence similarity, they share homology within an AT-rich element previously shown to enhance phaseolin expression. DNA-protein binding assays showed that an arcelin promoter fragment successfully competes with the AT-rich phaseolin promoter fragment for one or more nuclear factors... |
|---|---|
| Item Description: | Typescript (photocopy). Vita. "Major subject: Biology." |
| Physical Description: | x, 86 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |