An approach to the study of the maize NADP-malic enzyme family.

CLARISA ALVAREZ; SAIGO, MARIANA; ANDREO, CARLOS S; MARIA FABIANA DRINCOVICH

Tucumán

Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2009

SAIB

Genes encoding enzymes of the C4 cycle often belong to gene families having multiple copies. These findings led to the proposition that gene duplication, followed by functional innovation, was the genetic foundation for photosynthetic pathway transformation. In our studies on maize NADP-Malic Enzyme family we have isolated five transcripts encoding this enzyme The aim of this work was to study the role of each member of maize NADP-ME family. Predictive analyses and previous experiments clearly indicated that two proteins localize in the cytosol (ZmME3 and ZmME7) and two in the plastids (ZmME1 and ZmME2). On the other hand, ZmME4 amino terminal extension shows multiple transcription initiation sites and secondary structure that could reflect a complex transcription/translation regulation. Finally, as an approach to the functional annotation of each isoform, we performed a semi-quantitative analysis of each NADP-ME display in various tissues of maize, such as leaves, roots, grains, panicles, tassels, and embryos. The different expression indicating multiple functions of this gene family in maize. The recently available full genome sequence of sorghum, another C4 type grass, allowed us to discover that each maize isoform has a corresponding counterpart in sorghum, which may imply that certain NADP-ME fulfil particular roles in C4 metabolism