RESUMO
The use of plants as integral components of life support systems remains a cornerstone of strategies for long-term human habitation of space and extraterrestrial colonization. Spaceflight experiments over the past few decades have refined the hardware required to grow plants in low-earth orbit and have illuminated fundamental issues regarding spaceflight effects on plant growth and development. Potential incipient hypoxia, resulting from the lack of convection-driven gas movement, has emerged as a possible major impact of microgravity. We developed transgenic Arabidopsis containing the alcohol dehydrogenase (Adh) gene promoter linked to the beta-glucuronidase (GUS) reporter gene to address specifically the possibility that spaceflight induces the plant hypoxia response and to assess whether any spaceflight response was similar to control terrestrial hypoxia-induced gene expression patterns. The staining patterns resulting from a 5-d mission on the orbiter Columbia during mission STS-93 indicate that the Adh/GUS reporter gene was activated in roots during the flight. However, the patterns of expression were not identical to terrestrial control inductions. Moreover, although terrestrial hypoxia induces Adh/GUS expression in the shoot apex, no apex staining was observed in the spaceflight plants. This indicates that either the normal hypoxia response signaling is impaired in spaceflight or that spaceflight inappropriately induces Adh/GUS activity for reasons other than hypoxia.
Assuntos
Arabidopsis/metabolismo , Transdução de Sinais/genética , Voo Espacial , Transgenes , Álcool Desidrogenase/genética , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Cálcio/metabolismo , Glucuronidase/genética , Oxigênio/metabolismo , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismoRESUMO
It has been demonstrated that 14-3-3 proteins are present in the nuclei of Arabidopsis thaliana and Zea mays cells using laser scanning confocal microscopy and immunocytochemistry with monoclonal antibodies against plant 14-3-3 proteins. Confirmation of nuclear localization provides insight into the range of functions normally attributed to 14-3-3 proteins, especially since the association of 14-3-3s with transcription factors is (thus far) a phenomenon unique to plants, and since 14-3-3 proteins do not possess a recognizable nuclear targeting sequence.
