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Characterisation of the gene family encoding acetoacetyl-CoA thiolase in Arabidopsis

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  • Iván Ahumada
  • Albert Cairó
  • Andréa Hemmerlin
  • Víctor González
  • Pateraki, Irini
  • Thomas J. Bach
  • Manuel Rodríguez-Concepción
  • Narciso Campos
  • Albert Boronat

Thiolases are ubiquitous enzymes involved in many essential biochemical processes. Biosynthetic thiolases, also known as acetoacetyl-CoA thiolases (AACT), catalyse a reversible Claisen-type condensation of two acetyl-CoA molecules to form acetoacetyl-CoA. Here, we report the characterisation of two genes from Arabidopsis thaliana L., ACT1 and ACT2, which encode two closely related AACT isoforms (AACT1 and AACT2, respectively). Transient expression of constructs encoding AACT1 and AACT2 fused to GFP revealed that the two proteins show a different subcellular localisation. While AACT1 is found in peroxisomes, AACT2 localises in the cytosol and the nucleus. The peroxisomal localisation of AACT1 depends on the presence of a C-terminal peroxisomal targeting sequence (PTS1) motif (Ser-Ala-Leu) not previously found in other organisms. ACT1 and ACT2 genes are also differentially expressed. Whereas ACT2 is expressed at relatively high level in all plant tissues, the expression of ACT1 is restricted to roots and inflorescences and its transcript is present at very low levels. The obtained results are in agreement with the involvement of AACT2 in catalysing the first step of the mevalonate pathway. The metabolic function of AACT1 is not clear at present, although its particular peroxisomal localisation might exclude a role in isoprenoid biosynthesis.

OriginalsprogEngelsk
TidsskriftFunctional Plant Biology
Vol/bind35
Udgave nummer11
Sider (fra-til)1100-1111
Antal sider12
ISSN1445-4408
DOI
StatusUdgivet - 9 dec. 2008
Eksternt udgivetJa

ID: 131465277