Characterization of AtCDC48. Evidence for multiple membrane fusion mechanisms at the plane of cell division in plants.

The components of the cellular machinery that accomplish the various complex and dynamic membrane fusion events that occur at the division plane during plant cytokinesis, including assembly of the cell plate, are not fully understood. The most well-characterized component, KNOLLE, a cell plate-specific soluble N-ethylmaleimide-sensitive fusion protein (NSF)-attachment protein receptor (SNARE), is a membrane fusion machine component required for plant cytokinesis. Here, we show the plant ortholog of Cdc48p/p97, AtCDC48, colocalizes at the division plane in dividing Arabidopsis cells with KNOLLE and another SNARE, the plant ortholog of syntaxin 5, SYP31.

The expression of SpRunt during sea urchin embryogenesis.

The runt box (runx) is a highly conserved DNA binding and protein-protein interaction domain that defines a family of heterodimeric transcription factors that regulate development in metazoans. The three mammalian runx genes are oncogenes with essential functions in normal development: Runx1 is required for hematopoiesis and is frequently mutated in human and murine leukemias; Runx2 is required for bone development and is associated with human cleidocranial dysplasia and murine leukemias; and Runx3 (the evolutionarily basal member of the mammalian family) regulates growth of the gut and functions as a tumor suppressor in the gastric epithelium (Westendorf and Hiebert, 1999; Li et al., 2002).