A hypothetical gene with similarity to the ispD gene of Escherichia coli was cloned from Arabidopsis thaliana cDNA. The ORF of 909 bp specifies a protein of 302 amino acid residues. The cognate chromosomal gene consists of 2,071 bp and comprises 11 introns with a size range of 78–202 bp. A fragment comprising amino acid residues 76–302 was expressed in a recombinant E. coli strain.
Numb and Notch signalling pathways are vitally important in cell fate and differentiation. The outcome of these signalling processes is determined by a delicate balance between opposing effects of Notch and Numb. Imbalance in Numb/Notch regulation was implicated in aberrant differentiation programme and epithelial cancer progression and metastasis.