Participation of AtFH in the biogenesis of heme-containing proteins

MALIANDI, M. V.; BUSI, M. V.; DIEGO FABIAN GOMEZ CASATI

Carlos Paz, Argentina

Congreso; XLIV Reunión SAIB; 2008

SAIB

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Frataxin, a nuclear-encoded mitochondrial protein, has been proposed to participate in Fe–S cluster assembly, mitochondrial energy metabolism, respiration, and iron homeostasis. However, its precise function remains elusive. Mutations in the frataxin gene cause a reduced expression of this gene and an inherited recesive ataxia (Friedreich´s ataxia, FRDA). The analysis of Arabidopsis thaliana T-DNA insertional mutants deficient in AtFH expression suggest that AtFH is involved in Fe-S protein biogenesis in plant mitochondria. In the present work, we evaluate the effect of frataxin deficiency in heme synthesis in Arabidopsis plants. The analysis of a knock down mutant atfh-1 and antisense as-atfh plants revealed that both lines have similar amounts of catalase proteins compared to wt, but reduced heme content and also a decrease in total catalase activity (an heme-containing protein) compared with wt. Indeed, the addition of exogenous hemin rescues the catalase activity in leaves and flowers homogenates. Taken together, the results suggest that AtFH could be involved in the biogenesis of hemoproteins in Arabidopsis plants.