Could p21 antibody pave the way to new limb growth?

P21 antibody studies have significantly enhanced our understanding of cell cycle progression. P21 is a potent CKI (cyclin-dependent kinase inhibitor) which regulates cell-cycle progression at the S-phase by inhibition of two cyclin/CDK complexes, enabling cell differentiation to occur. Novus’ p21 antibodies are widely used in cell cycle and replication research.

P21 is known to have a conserved binding site for the HuD (ELAVL4) protein, which regulates mRNA stability and neuronal differentiation (Joseph et al, 1999.) This showed a link between cellular differentiation, mRNA stability and cell cycle termination. Further studies demonstrated roles in cellular aging and DNA repair. P21 may be instrumental in initiating apoptosis; however, it does not stimulate apoptosis independently. Expression is tightly regulated by the tumour suppressor p53, with overexpression inhibiting cellular proliferation. However, p21 can also be expressed in the absence of p53 and has been seen at elevated levels in metastatic canine tumours.

Tissue regeneration is thought to only be conserved in lower animals, with mammals repairing damage by formation of scar tissue. However, a recent study by the Wistar Institute showed that mice deficient in the P21 gene were able to regenerate missing or damaged tissue by the formation of a blastema similar to that seen in amphibians. Blastemas are formed from rapidly proliferating, non-differentiated cells. It was suggested the absence of p21 enabled adult mammalian cells to regain ESC (embryonic stem cell) functionality.

Earlier p21 antibody experiments on a naturally-deficient strain of mice had shown similar results, together with an enhanced rate of apoptosis – another trait seen in salamanders. Therefore, researchers are using Novus’ p21 reagents to develop novel therapies for human tissue regeneration without scarring.