ATCOX10, implicated in heme a biosynthesis for COX assembly, is essential for plant embryogenesis.

MANSILLA, NATANAEL; GARCÍA, LUCILA; GONZALEZ, DANIEL H.; WELCHEN, ELINA.

Congreso; XLVII Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular (SAIB).; 2011

Cytochrome c oxidase (COX) biogenesis requires more than 20 accessory proteins implicated, among other processes, in copper and heme a insertion. COX10, a farnesyltransferase that catalyzes the conversion of heme b to heme o, is the limiting factor in heme a biosynthesis and would be essential for its insertion in the COX1 subunit in yeast. In order to elucidate the function of COX10 in plants, we have studied Arabidopsis mutant plants with a T-DNA insertion in the coding region of the AtCOX10 gene. It was not possible to obtain AtCOX10 knockout plants and segregation analysis of heterozygote mutants suggested that AtCOX10 function is required during embryogenesis. Siliques of these plants contained 25% abnormal seeds with embryos arrested at early stages of development. In addition, heterozygote mutants entered senescence before wild-type plants, suggesting a function of AtCOX10 during this process. We analyzed the expression of AtCOX10 by using promoter fusions to the GUS reporter. Supporting the hypothesis of a coordinated expression of genes required for COX biogenesis, we observed high expression of the reporter in anthers. As we observed previously for other COX assembly factors, the expression of AtCOX10 is essential during early stages of plant development, indicating the requirement of active COX biogenesis and respiratory activity during embryogenesis.