Keratin 21

Keratin 21 is a type I cytokeratin which expresses immunologically specific fusion protein. It is not found in humans, but only in Rattus norvegicus. It is first detectable after 18-19 days of gestation. ^[1]

References

1. Quaroni, A.; Calnek, D.; Quaroni, E.; Chandler, J. S. (25 June 1991). "Keratin expression in rat intestinal crypt and villus cells. Analysis with a panel of monoclonal antibodies". Journal of Biological Chemistry. 266 (18): 11923–11931. doi:10.1016/S0021-9258(18)99046-0. ISSN 0021-9258. PMID 1711043. Retrieved 4 December 2022.