Molecular cloning of a chick cochlea cDNA encoding a subunit of DNA replication factor C/activator 1

A chick cochlea cDNA library was constructed to clone molecules involved in peripheral auditory transduction and in the maintenance and regeneration of the sensory neuroepithelium following damage. Characterization of the library showed it to be of high complexity, to contain a high proportion of full-length cDNA inserts, and to contain a representative proportion of clones derived from hair cell transcripts. A cDNA clone encoding the chick homolog of the 40-kD subunit of the human replication factor C (also called activator 1) was isolated and the complete cDNA sequence determined. The predicted amino acid sequence is about 90% identical to that of the human homolog. Expression of the message for this replication factor was detected in brain and liver as well as in the cochlea. Expression levels in the brain are relatively high and are similar in developing and adult chicken nervous tissue. This suggests that replication factor C message expression, unlike that for the functionally associated factor proliferating cell nuclear antigen (PCNA), may be constitutive rather than cell cycle dependent. Although likely to be involved in DNA replication within the receptor neuroepithelium, expression of this replication factor message is not likely to constitute a marker for proliferation.