Progress 07/01/01 to 09/30/05
Outputs
Endosperm initiation is controlled by double fertilization in angiosperms. The uncoupling of these two events is observed in the Arabidopsis fis/fie (fertilization-independent seed/endosperm) class of mutants defective in Polycomb-group (PcG) function, including mea, fie, fis2, and msi1. In Arabidopsis, the SET-domain PcG (MEA family) and Zinc-finger PcG (FIS2 family) proteins are encoded by a few genes with divergent developmental functions that include roles in early seed development, control of flowering time and regulation of vernalization. The divergent roles of PcG proteins suggest that plants utilize distinct PcG complexes to regulate different developmental processes. Using a yeast-2-hybrid screen, we have identified MEA and EZA1 (a.k.a. SWINGER) as distinct SET-domain partners of FIS2 during early seed development. Mapping of the FIS2-interacting regions indicated that the two SET-domain proteins may have diverged functionally due to changes in a region
containing five cysteines. Moreover, protein localization experiments indicated a more ubiquitous pattern of expression for EZA1 as compared to MEA. Finally, mutations in the EZA1 gene enhanced mea mutant phenotypes including parthenocarpic development and formation of autonomous endosperm. As EZA1 has been implicated in flowering timing control, our data indicate that EZA1 and MEA perform partially-overlapping yet distinct functions during plant development.
Impacts
Our research will contribute to a better understanding of how the processes of female gametophyte development and fertilization control the initiation and early development of endosperm, an essential component required for angiosperm reproduction. Our studies will provide a valuable source of information about the regulation of endosperm development, the component of seed that constitutes the most important renewable source for food, feed, and industrial material.
Publications
- No publications reported this period
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Progress 01/01/04 to 12/31/04
Outputs
An important component of our Hatch project was the identification of regulatory components involved in initiation of endosperm development. Endosperm initiation is controlled by double fertilization in angiosperms. The uncoupling of these two events is observed in the Arabidopsis fis/fie (fertilization independent seed/endosperm) class of mutants defective in Polycomb-group (PcG) function, including mea, fie, fis2, and msi1. In Arabidopsis, the SET-domain PcG (MEA family) and Zinc-finger PcG (FIS2 family) proteins are encoded by a few genes with divergent developmental functions that include roles in early seed development, control of flowering time and regulation of vernalization. The divergent roles of PcG proteins suggest that plants utilize distinct PcG complexes to regulate different developmental processes. Using a yeast-2-hybrid screen, we have identified MEA and EZA1 (a.k.a. SWINGER) as distinct SET-domain partners of FIS2 during early seed development.
Mapping of the FIS2-interacting regions indicated that the two SET-domain proteins may have diverged functionally due to changes in a region containing five cysteines. Moreover, protein localization experiments indicated a more ubiquitous pattern of expression for EZA1 as compared to MEA. Finally, mutations in the EZA1 gene enhanced mea mutant phenotypes including parthenocarpic development and formation of autonomous endosperm. As EZA1 has been implicated in flowering timing control, our data indicate that EZA1 and MEA perform partially-overlapping yet distinct functions during plant development. Our work is contributing to an understanding of how PcG complexes control development of major transition points in the life cycle of the plant.
Impacts
Our research will contribute to a better understanding of how the processes of female gametophyte development and fertilization control the initiation and early development of endosperm, an essential component required for angiosperm reproduction. Our studies will provide a valuable source of information about the regulation of endosperm development, the component of seed that constitutes the most important renewable source for food, feed, and industrial material.
Publications
- No publications reported this period
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Progress 01/01/03 to 12/31/03
Outputs
Recently, we have concentrated our efforts on the study of a polycomb-group complex of proteins required for early endosperm proliferation in Arabidopsis. Specifically, we have been studying the function and regulation of FIS2, a zinc-finger polycomb protein during late female gametophyte development and early endosperm development. We are currently analyzing the regulation of FIS2 gene expression and the identity of the proteins it interact with.
Impacts
Our research will contribute to a better understanding of how the processes of female gametophyte development and fertilization control the initiation and early development of endosperm, an essential component required for angiosperm reproduction. Our studies will provide a valuable source of information about the regulation of endosperm development, the component of seed that constitutes the most important renewable source for food, feed, and industrial material.
Publications
- No publications reported this period
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Progress 01/01/02 to 12/31/02
Outputs
We have been using the Arabidopsis FIS2 gene as an entry point into the regulatory networks that link the development of the female gametophyte with fertilization and early endosperm development. We have been analyzing the FIS2 gene expression pattern and testing whether the FIS2 gene is silenced differentially in the endosperm or embryo. The latter will permit us to investigate a potential role for FIS2 imprinting in endosperm development. Our results indicate a specific pattern of reporter gene expression in the central cell before fertilization and in early-developing endosperm after fertilization. We have recently begun to identify regulatory sequences flanking the FIS2 gene. In addition, we have found an important role for 5'UTR squences in the regulation of FIS2 gene expression. We have also undertaken identification of additional genes that function within the female gametophyte to control seed development using a forward genetic screen.
Impacts
Our long-term goal is to understand the regulatory processes that control endosperm initiation and early development. Endosperm is unique to angiosperms and is thought to have played a critical role in their evolutionary success. From an economic perspective, endosperm constitutes the most important renewable source for food, feed, and industrial material. Despite its importance for plant development, only recently the molecular processes that regulate endosperm initiation and development are beginning to be deciphered.
Publications
- No publications reported this period
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Progress 01/01/01 to 12/31/01
Outputs
We have been using the Arabidopsis FIS2 gene as an entry point into the regulatory networks that link the development of the female gametophyte with fertilization and early endosperm development. We have been analyzing the FIS2 gene expression pattern and testing whether the FIS2 gene is silenced differentially in the endosperm or embryo. The latter will permit us to investigate a potential role for FIS2 imprinting in endosperm development. Our results indicate a specific pattern of reporter gene expression in the central cell before fertilization and in early-developing endosperm after fertilization. We have not detected any FIS2::Reporter gene expression anywhere else in the plant. We have recently begun to identify regulatory sequences flanking the FIS2 gene. We have also undertaken identification of additional genes that are expressed during late female gametophyte development and early endosperm development in order to generate a profile of gene regulatory
networks active in this crucial stage of development.
Impacts
Endosperm is unique to angiosperms and is thought to have played a critical role in their evolutionary success. Our long-term goal is to understand the regulatory processes that control the development of endosperm, the component of seed that constitutes the most important renewable source for food, feed, and industrial material.
Publications
- No publications reported this period
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