Multiple FtsZ2 isoforms involved in chloroplast division and biogenesis are developmentally associated with thylakoid membranes in Arabidopsis.

Seed plants and algae have two distinct FtsZ protein families, FtsZ1 and FtsZ2, involved in plastid division. Distinctively, seed plants and mosses contain two FtsZ2 family members (FtsZ2-1 and FtsZ2-2) thus raising the question of the role of these FtsZ2 paralogs in plants. We show that both FtsZ2 paralogs, in addition to being present in the stroma, are associated with the thylakoid membranes and that association is developmentally regulated.

Developmentally regulated association of plastid division protein FtsZ1 with thylakoid membranes in Arabidopsis thaliana.

FtsZ is a key protein involved in bacterial and organellar division. Bacteria have only one ftsZ gene, while chlorophytes (higher plants and green alga) have two distinct FtsZ gene families, named FtsZ1 and FtsZ2. This raises the question of why chloroplasts in these organisms need distinct FtsZ proteins to divide.

Characterization of a ubiquitous expressed gene family encoding polygalacturonase in Arabidopsis thaliana.

Pectin, as one of the major components of plant cell wall, has been implicated in many developmental processes occurring during plant growth. Among the different enzymes known to participate in the pectin structure modifications, polygalacturonase (PG) activity has been shown to be associated with fruit ripening, organ abscission and pollen grain development. Until now, sequence analyses of the deduced polypeptides of the plant PG genes allowed their grouping into three clades corresponding to genes involved in one of these three activities.

Differential expression of a polygalacturonase gene family in Arabidopsis thaliana.

By systematic sequencing of a flower bud cDNA library from Arabidopsis thaliana, we have identified four cDNAs encoding polygalacturonase. The corresponding genes, together with seven other A. thaliana genes present in the databases, form a small gene family.

RGD-dependent growth of maize calluses and immunodetection of an integrin-like protein.

When maize calluses are grown in the presence of the RGD peptide, important morphological changes are observed indicating the presence of a likely RGD-binding receptor. Polyclonal antibodies generated against the human beta1 integrin subunit, the platelet integrin alphaIIbeta3 (P23) and antibodies specific for either the beta3 platelet chain or the alphaIIb polypeptide cross-react with glycoproteins in Western blot analyses. Immunoprecipitation assays indicate that this maize integrin-like protein shares structural similarities with the animal alphaIIbeta3 complex.