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Minako Ueda

Publications and source records attributed to Minako Ueda.

3 recordsLinked to original sources
PubMed2005

Stepwise understanding of root development.

Recent studies using Arabidopsis propose a framework of root development and pattern formation that can be divided to three processes. First, a positional signal that is delivered from neighboring cells controls the fate of undifferentiated cells. Then, cell fate is fixed through a protein-network that includes various transcription factors. Finally, the expression of a particular gene-set leads to fate-dependent cell differentiation, resulting in oriented cell division, cell specification and cell elongation. In addition, these processes could be modified by chromatin stabilization and protein degradation. We focus on three fundamental patterns of root development, circumferential pattern, radial pattern and proximo-distal pattern, and on novel approaches to identify genes that are responsible for the spatiotemporal regulation of root development.

Arabidopsis↗
PubMed2004

The HALTED ROOT gene encoding the 26S proteasome subunit RPT2a is essential for the maintenance of Arabidopsis meristems.

In higher plants, post-embryonic development is dependent on the activity of the root and shoot apical meristem (RAM and SAM). The quiescent center (QC) in the RAM and the organizing center (OC) in the SAM are known to be essential for the maintenance of meristematic activity. To understand the mechanism that maintains post-embryonic meristems, we isolated an Arabidopsis mutant, halted root (hlr). In this mutant, the cellular organization was disrupted in post-embryonic meristems both in the root and in the shoot, and their meristematic activity was reduced or became abnormal. We showed that the mutant RAM lost its QC identity after germination, which was specified during embryogenesis, whereas the identity of differentiated tissues was maintained. In the post-embryonic SAM, the expression pattern of a typical OC marker gene, WUSCHEL, was disturbed in the mutant. These observations indicate that the HLR gene is essential to maintain the cellular organization and normal nature of the RAM and SAM. The HLR gene encodes RPT2a, which is a subunit of the 26S proteasome that degrades key proteins in diverse cellular processes. We showed that the HLR gene was expressed both in the RAM and in the SAM, including in the QC and the OC, respectively, and that the activity of proteasomes were reduced in the mutant. We propose that proteasome-dependent programmed proteolysis is required to maintain the meristem integrity both in the shoot and in the root.

Amino Acid Sequence↗