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T S Tseng

Publications and source records attributed to T S Tseng.

5 recordsLinked to original sources
PubMed2001

The role of SPY and its TPR domain in the regulation of gibberellin action throughout the life cycle of Petunia hybrida plants.

SPY acts as a negative regulator of gibberellin (GA) action in Arabidopsis, but its mode of action and regulation are still unknown. SPY over-expression in transgenic petunia plants affected various GA-regulated processes, including seed germination, shoot elongation, flower initiation, flower development and the expression of a GA-induced gene, GIP. A similar phenotype was obtained when wild-type petunia plants were treated with the GA-biosynthesis inhibitor, paclobutrazol. The N-terminus of SPY contains tetratricopeptide repeats (TPR). TPR motifs participate in protein-protein interactions, suggesting that SPY is part of a multiprotein complex. To test this hypothesis, we over-expressed the SPY's TPR region without the catalytic domain in transgenic petunia and generated a dominant-negative SPY mutant. The transgenic seeds were able to germinate on paclobutrazol, suggesting an enhanced GA signal. We cloned the petunia SPY homologue, PhSPY, and showed that its mRNA level is not affected by GA or ABA. The results of this study support the role of SPY as a negative regulator of GA action, suggest that the TPR domain is required for the interaction with other proteins to form an active complex and indicate that different plants use similar mechanisms to transduce the GA signal.

Amino Acid Sequence↗
PubMed2001

Altered expression of SPINDLY affects gibberellin response and plant development.

Gibberellins (GAs) are plant hormones with diverse roles in plant growth and development. SPINDLY (SPY) is one of several genes identified in Arabidopsis that are involved in GA response and it is thought to encode an O-GlcNAc transferase. Genetic analysis suggests that SPY negatively regulates GA response. To test the hypothesis that SPY acts specifically as a negatively acting component of GA signal transduction, spy mutants and plants containing a 35S:SPY construct have been examined. A detailed investigation of the spy mutant phenotype suggests that SPY may play a role in plant development beyond its role in GA signaling. Consistent with this suggestion, the analysis of spy er plants suggests that the ERECTA (ER) gene, which has not been implicated as having a role in GA signaling, appears to enhance the non-GA spy mutant phenotypes. Arabidopsis plants containing a 35S:SPY construct possess reduced GA response at seed germination, but also possess phenotypes consistent with increased GA response, although not identical to spy mutants, during later vegetative and reproductive development. Based on these results, the hypothesis that SPY is specific for GA signaling is rejected. Instead, it is proposed that SPY is a negative regulator of GA response that has additional roles in plant development.

Arabidopsis Proteins↗
PubMed2001

Ectopic expression of the tetratricopeptide repeat domain of SPINDLY causes defects in gibberellin response.

The SPINDLY (SPY) protein of Arabidopsis is a negative regulator of gibberellin (GA) response. The SPY protein has 10 copies of the tetratricopeptide repeat (TPR) at the N terminus. TPR motifs function as protein-protein interaction domains. Several spy alleles are affected only in the TPR region suggesting that protein-protein interactions mediated by this domain are important for proper GA signaling. We have used a reverse genetics approach to further investigate the role of the TPR domain. The TPR domain of SPY was overexpressed in wild-type, gai, and spy plants. Expression of the TPR domain alone is not sufficient to rescue spy mutants. Expression of the TPR domain in a wild-type background produces phenotypes similar to those caused by loss-of-function spy mutants including resistance to GA biosynthesis inhibitors, short hypocotyl length, and early flowering. The dwarfing of the floral shoot internodes caused by the gai mutation was suppressed by expression of the TRP domain. Expression of the TPR domain had no effect on the abundance of endogenous SPY mRNA. The TPR domain was found to interact with SPY both in vitro and in yeast two-hybrid assays. These data indicate that the TPR domain of SPY can participate in protein-protein interactions and that these interactions are important for the proper functioning of SPY.

Arabidopsis↗
PubMed1991

Sphenoidal EEG recording using acupuncture needle electrode in complex partial seizure.

Sphenoidal EEG recording using an uninsulated acupuncture needle electrode were performed in 41 patients with or suspected of complex partial seizures of temporal lobe origin. The anterior temporal spikes were detected by the routine EEG in 17 patients (41%) and by the acupuncture sphenoidal needle in 29 patients (70%). The anterior temporal spikes recorded by the acupuncture needle were almost identical in configuration, amplitude and distribution to those recorded by conventional wire or insulated needle sphenoidal electrodes. The sequence in the frequency of spike detection by these 3 types of sphenoidal electrode were SP1-2, T1-2, F7-8 and A1-2 locations. The spikes of maximal amplitude were most frequently recorded by the SP electrode followed by the T1-2 electrode. The placement of the disposable acupuncture needle was simple and safe. Patients experienced minimal discomfort or pain that lasted at most 0.5 h. No complications occurred. The records were generally free of artifacts. It is concluded that the acupuncture needle can be used as sphenoidal electrode in outpatient EEG recording for the diagnosis of complex partial seizures of anterior temporal-origin.

Action Potentials↗