Effect of ATP sulfurylase overexpression in bright yellow 2 tobacco cells. Regulation Of atp sulfurylase and SO4(2-) transport activities.
To determine if the ATP sulfurylase reaction is a regulatory step for the SO4(2-)-assimilation pathway in plants, an Arabidopsis thaliana ATP sulfurylase cDNA, APS2, was fused to the 35S promoter of the cauliflower mosaic virus and introduced by Agrobacterium tumefaciens-mediated transformation into isolated Bright Yellow 2 tobacco (Nicotiana tabacum) cells. The ATP sulfurylase activity in transgenic cells was 8-fold that in control cells, and was correlated with the expression of a specific polypeptide revealed by western analysis using an anti-ATP sulfurylase antibody. The molecular mass of this polypeptide agreed with that for the overexpressed mature protein. ATP sulfurylase overexpression had no effect on [35S]SO4(2-) influx or ATP sulfurylase activity regulation by S availability, except that ATP sulfurylase activity variations in response to S starvation in transgenic cells were 8 times higher than in the wild type. There were also no differences in cell growth or sensitivity to SeO4(2-) (a toxic SO4(2-) analog) between transgenic and wild-type cells. We propose that in Bright Yellow 2 tobacco cells, the ATP sulfurylase derepression by S deficiency may involve a posttranscriptional mechanism, and that the ATP sulfurylase abundance is not limiting for cell metabolism.
Hatzfeld
Y
Y
Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Ecole Nationale Supérieure Agronomique de Montpellier, Cedex, France.
Cathala
N
N
Grignon
C
C
Davidian
J C
JC
D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D002455:Cell Division; D002478:Cells, Cultured; D003001:Cloning, Molecular; D015870:Gene Expression; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D064586:Selenic Acid; D018036:Selenium Compounds / Q000378:metabolism; D013430:Sulfate Adenylyltransferase / Q000235:genetics / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism*; D014026:Nicotiana
D018036:Selenium Compounds; D013431:Sulfates; D013430:Sulfate Adenylyltransferase; D064586:Selenic Acid