Cloning of cDNA encoding a 100 kDa nudeolar protein (nucleoline) of Chinese hamster ovary cells

Open Access
Publisher Website
Google Scholar
Abstract
Nucleoline (100 kDa) is the major nucleolar protein in exponentially growing cells that behaves like a nucleolar organizer protein and plays a key role in rDNA transcription and prerRNA processing. We reported the isolation of 5 cDNA clones by probing a cDNA library, constructed in the expression vector λ gt11, with a polyclonal serum raised against nudeoline. A new immunoassay, using hybrid proteins (βgal-cDNA encoded protein)was developped to establish that the isolated cDNAs encoded parts of nucleoline. A further confirmation resulted from the sequence comparison between the cDNA encoded peptide and a 42 aa peptide isolated from rat nudeoline (1). The 5 cDNAs overlapped extensively and covered more than 90 % of a full length cDNA. By probing a Northern blot with the 100kDa cDNA, a 2650 nucleotide polyA+ RNA was detected that contained just enough information to code for nucleoline.