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Dive into the research topics where Michael F. Portereiko is active.

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Featured researches published by Michael F. Portereiko.


The Plant Cell | 2005

MYB98 Is Required for Pollen Tube Guidance and Synergid Cell Differentiation in Arabidopsis

Ryushiro D. Kasahara; Michael F. Portereiko; Linda Sandaklie-Nikolova; David S. Rabiger; Gary N. Drews

The synergid cells of the female gametophyte play a role in many steps of the angiosperm fertilization process, including guidance of pollen tube growth to the female gametophyte. However, the mechanisms by which the synergid cells become specified and develop their unique features during female gametophyte development are not understood. We identified MYB98 in a screen for Arabidopsis thaliana genes expressed in the female gametophyte. MYB98 is a member of the R2R3-MYB gene family, the members of which likely encode transcription factors. In the context of the ovule, MYB98 is expressed exclusively in the synergid cells, and mutations in this gene affect the female gametophyte specifically. myb98 female gametophytes are affected in two unique features of the synergid cell, pollen tube guidance and the filiform apparatus, but are otherwise normal. MYB98 also is expressed in trichomes and endosperm. Homozygous myb98 mutants exhibit no sporophytic defects, including trichome and endosperm defects. Together, these data suggest that MYB98 controls the development of specific features within the synergid cell during female gametophyte development.


The Plant Cell | 2006

AGL80 Is Required for Central Cell and Endosperm Development in Arabidopsis

Michael F. Portereiko; Alan Lloyd; Joshua G. Steffen; Jayson A. Punwani; Denichiro Otsuga; Gary N. Drews

During plant reproduction, the central cell of the female gametophyte becomes fertilized to produce the endosperm, a storage tissue that nourishes the developing embryo within the seed. The molecular mechanisms controlling the specification and differentiation of the central cell are poorly understood. We identified a female gametophyte mutant in Arabidopsis thaliana, fem111, that is affected in central cell development. In fem111 female gametophytes, the central cells nucleolus and vacuole fail to mature properly. In addition, endosperm development is not initiated after fertilization of fem111 female gametophytes. fem111 contains a T-DNA insertion in AGAMOUS-LIKE80 (AGL80). FEM111/AGL80 is a member of the MADS box family of genes that likely encode transcription factors. An AGL80–green fluorescent protein fusion protein is localized to the nucleus. Within the ovule and seed, FEM111/AGL80 is expressed exclusively in the central cell and uncellularized endosperm. FEM111/AGL80 expression is also detected in roots, leaves, floral stems, anthers, and young flowers by real-time RT-PCR. FEM111/AGL80 is required for the expression of two central cell–expressed genes, DEMETER and DD46, but not for a third central cell–expressed gene, FERTILIZATION-INDEPENDENT SEED2. Together, these data suggest that FEM111/AGL80 functions as a transcription factor within the central cell gene regulatory network and controls the expression of downstream genes required for central cell development and function.


The Plant Cell | 2008

The AGL62 MADS Domain Protein Regulates Cellularization during Endosperm Development in Arabidopsis

Il Ho Kang; Joshua G. Steffen; Michael F. Portereiko; Alan Lloyd; Gary N. Drews

Endosperm, a storage tissue in the angiosperm seed, provides nutrients to the embryo during seed development and/or to the developing seedling during germination. A major event in endosperm development is the transition between the syncytial phase, during which the endosperm nuclei undergo many rounds of mitosis without cytokinesis, and the cellularized phase, during which cell walls form around the endosperm nuclei. The molecular processes controlling this phase transition are not understood. In agl62 seeds, the endosperm cellularizes prematurely, indicating that AGL62 is required for suppression of cellularization during the syncytial phase. AGL62 encodes a Type I MADS domain protein that likely functions as a transcription factor. During seed development, AGL62 is expressed exclusively in the endosperm. During wild-type endosperm development, AGL62 expression is strong during the syncytial phase and then declines abruptly just before cellularization. By contrast, in mutant seeds containing defects in some FERTILIZATION-INDEPENDENT SEED (FIS) class Polycomb group genes, the endosperm fails to cellularize and AGL62 expression fails to decline. Together, these data suggest that AGL62 suppresses cellularization during the syncytial phase of endosperm development and that endosperm cellularization is triggered via direct or indirect AGL62 inactivation by the FIS polycomb complex.


Plant Physiology | 2008

AGL61 Interacts with AGL80 and Is Required for Central Cell Development in Arabidopsis

Joshua G. Steffen; Il Ho Kang; Michael F. Portereiko; Alan Lloyd; Gary N. Drews

The central cell of the female gametophyte plays a role in pollen tube guidance and in regulating the initiation of endosperm development. Following fertilization, the central cell gives rise to the seeds endosperm, which nourishes the developing embryo within the seed. The molecular mechanisms controlling specification and differentiation of the central cell are poorly understood. We identified AGL61 in a screen for transcription factor genes expressed in the female gametophyte. AGL61 encodes a Type I MADS domain protein, which likely functions as a transcription factor. Consistent with this, an AGL61-green fluorescent protein fusion protein is localized to the nucleus. In the context of the ovule and seed, AGL61 is expressed exclusively in the central cell and early endosperm. agl61 female gametophytes are affected in the central cell specifically. The morphological defects include an overall reduction in size of the central cell and a reduced or absent central cell vacuole. When fertilized with wild-type pollen, agl61 central cells fail to give rise to endosperm. In addition, synergid- and antipodal-expressed genes are ectopically expressed in agl61 central cells. The expression pattern and mutant phenotype of AGL61 are similar to those of AGL80, suggesting that AGL61 may function as a heterodimer with AGL80 within the central cell; consistent with this, AGL61 and AGL80 interact in yeast two-hybrid assays. Together, these data suggest that AGL61 functions as a transcription factor and controls the expression of downstream genes during central cell development.


Plant Physiology | 2006

NUCLEAR FUSION DEFECTIVE1 Encodes the Arabidopsis RPL21M Protein and Is Required for Karyogamy during Female Gametophyte Development and Fertilization

Michael F. Portereiko; Linda Sandaklie-Nikolova; Alan Lloyd; Chad A. Dever; Denichiro Otsuga; Gary N. Drews

Karyogamy, or nuclear fusion, is essential for sexual reproduction. In angiosperms, karyogamy occurs three times: twice during double fertilization of the egg cell and the central cell and once during female gametophyte development when the two polar nuclei fuse to form the diploid central cell nucleus. The molecular mechanisms controlling karyogamy are poorly understood. We have identified nine female gametophyte mutants in Arabidopsis (Arabidopsis thaliana), nuclear fusion defective1 (nfd1) to nfd9, that are defective in fusion of the polar nuclei. In the nfd1 to nfd6 mutants, failure of fusion of the polar nuclei is the only defect detected during megagametogenesis. nfd1 is also affected in karyogamy during double fertilization. Using transmission electron microscopy, we showed that nfd1 nuclei fail to undergo fusion of the outer nuclear membranes. nfd1 contains a T-DNA insertion in RPL21M that is predicted to encode the mitochondrial 50S ribosomal subunit L21, and a wild-type copy of this gene rescues the mutant phenotype. Consistent with the predicted function of this gene, an NFD1-green fluorescent protein fusion protein localizes to mitochondria and the NFD1/RPL21M gene is expressed throughout the plant. The nfd3, nfd4, nfd5, and nfd6 mutants also contain T-DNA insertions in genes predicted to encode proteins that localize to mitochondria, suggesting a role for this organelle in nuclear fusion.


Science | 2000

A Link Between RNA Interference and Nonsense-Mediated Decay in Caenorhabditis elegans

Mary Ellen Domeier; Daniel P. Morse; Scott W. Knight; Michael F. Portereiko; Brenda L. Bass; Susan E. Mango


Archive | 2007

Fruit regulatory regions

Joon-Hyun Park; Steven Craig Bobzin; Courtney A. Becker; Yiwen Fang; Zhihong C. Cook; Michael F. Portereiko


Archive | 2015

Methods and materials for improving yield under high density conditions

Roger I. Pennell; Richard Hamilton; Michael F. Portereiko


Archive | 2014

Methods and materials for high throughput testing of transgene combinations

Roger I. Pennell; Richard Hamilton; Michael F. Portereiko


Archive | 2013

MODULATING LIGHT RESPONSE PATHWAYS IN PLANTS, INCREASING LIGHT-RELATED TOLERANCES IN PLANTS, AND INCREASING BIOMASS IN PLANTS

Shing Kwok; Kenneth Bounds; Ryan Miller; Sam Harris; James E. Burns; Roger I. Pennell; Vijay Sharma; Michael F. Portereiko; Han-Suk Kim; Gerard Magpantay

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