Biomedical subjects

Shelley Lumba

Publications and source records attributed to Shelley Lumba.

2 recordsLinked to original sources

PubMed2005

Preventing leaf identity theft with hormones.

Genetic analysis of plant development has begun to demonstrate the importance of hormone synthesis and transport in regulating morphogenesis. In the case of leaf development, for example, auxin pooling determines where a primordium will emerge and leads to the activation of transcription factors, which determine leaf identities by modulating abscisic acid (ABA) and gibberellic acid (GA) concentrations. Signal transduction studies suggest that negative regulation of transcription factors through protein turnover is commonly used as a mechanism of hormone action. Together, these findings suggest that auxin might degrade a repressor that allows the activation of genes that modulate ABA/GA ratios in emerging leaves. With our increased understanding of the molecular basis of hormone signaling, it is becoming possible to overlay important regulators onto signaling modules that determine morphological outputs.

Abscisic Acid↗

PubMed2004

The transcription factor FUSCA3 controls developmental timing in Arabidopsis through the hormones gibberellin and abscisic acid.

Although plants continually produce different organs throughout their life cycle, little is known about the factors that regulate the timing of a given developmental program. Here we report that the restricted expression of FUS3 to the epidermis is sufficient to control foliar organ identity in Arabidopsis by regulating the synthesis of two hormones, abscisic acid and gibberellin. These hormones in turn regulate the rates of cell cycling during organ formation to determine whether an embryonic or adult leaf will emerge. We also show that FUS3 expression is influenced by the patterning hormone, auxin, and therefore acts as a nexus of hormone action during embryogenesis. The identification of lipophillic hormones downstream of a heterochronic regulator in Arabidopsis has parallels to mechanisms of developmental timing in animals and suggests a common logic for temporal control of developmental programs between these two kingdoms.

Abscisic Acid↗