Abstract
The tapetum is a nutritive tissue of the stamen that is essential for normal microspore development. While numerous tapetal-specific genes have been identified, little information is available on the localization and function of the proteins produced by these genes. The tapetally produced protein 5B-CRP is cysteine-rich, has a secretory signal sequence and lacks an endoplasmic reticulum retention sequence. The 5B-CRP mRNA is expressed specifically within the tapetum and accumulates from premeiosis to tetrad release. Antibodies generated against an Escherichia coli fusion protein only recognized 5B-CRP in the reduced state. The 5B-CRP was detected as a 6 kDa protein in extracts of stamens from microspore meiosis through anthesis and was also observed in extracts from dehisced pollen. In situ, 5B-CRP was localized in stamens to the tapetum and the developing microspores, from the tetrad through early free microspore stages. Based on similarity to proteins with known functions, 5B-CRP may inhibit proteasome activity within the stamen locule.
Original language | English (US) |
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Pages (from-to) | 457-464 |
Number of pages | 8 |
Journal | Journal of Plant Physiology |
Volume | 162 |
Issue number | 4 |
DOIs | |
State | Published - Apr 22 2005 |
Bibliographical note
Funding Information:This research was supported in part by the Minnesota Agricultural Experiment Station. Paper No. 031210124.
Keywords
- Cysteine-rich protein
- Exine
- Microspore
- Proteasome inhibitor
- Tapetum