Sequence analysis, transcriptional and posttranscriptional regulation of the rice vdac family.
The voltage-dependent anion-selective channel (VDAC) is a mitochondrial outer membrane ion channel. Different isoforms exist in plants but information about their specific role remains to be established. Our purpose is to find out the structural features common to three rice VDAC isoforms and to investigate their (post)transcriptional regulation in response to an osmotic stress. Two new cDNAs encoding mitochondrial VDAC from rice (Oryza sativa) were isolated, sequenced and characterized: a phylogenetic reconstruction permitted identification of orthologues in Poaceae and computer-based analyses predicted 18 transmembrane beta-strands, one amphipathic alpha-helix and two different phosphorylation motifs. The expression of three rice vdac genes was investigated. Northern blot analyses indicated that they were expressed in all plant tissues. There was a differential expression of osvdac1 and osvdac3, whereas osvdac2 was homogeneously expressed in all tissues. No change in vdac expression was observed under an osmotic stress. However, a fast-enhanced expression of vdac was observed in roots during the recovery period after stress release. This enhanced expression is not correlated to the amount of VDAC protein detected in roots suggesting a posttranscriptional regulation.
Al Bitar
Fawaz
F
Laboratoire de Physiologie Végétale, Université Libre de Bruxelles, Campus Plaine (CP 206/2), B-1050 Brussels, Belgium.
Roosens
Nancy
N
Smeyers
Mathias
M
Vauterin
Marc
M
Van Boxtel
Jos
J
Jacobs
Michel
M
Homblé
Fabrice
F
D018506:Gene Expression Regulation, Plant; D008353:Mannitol / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D012275:Oryza / Q000235:genetics*; D009997:Osmotic Pressure; D018272:Porins / Q000737:chemistry / Q000235:genetics*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics; D017433:Protein Structure, Secondary; D017422:Sequence Analysis, DNA; D050994:Voltage-Dependent Anion Channels
D018272:Porins; D020033:Protein Isoforms; D050994:Voltage-Dependent Anion Channels; D008353:Mannitol