CHARACTERIZATION OF CLONED AORTIC SMOOTH-MUSCLE CELLS FROM YOUNG-RATS

Clones were derived by dilute plating from cultured aortic smooth musc le cells of 12-day-old rats. Clones Pup I to III resemble uncloned smo oth muscle cultures from aortas of rat pups and from adult rat neointi mas. They have a cobblestone morphology and proliferate in plasma-deri ved serum. By Northern analysis they contain platelet-derived growth f actor B chain (PDGF-B) mRNA and high levels of CYPIA1, elastin, and os teopontin mRNAs, and they lack platelet-derived growth factor alpha-re ceptor (PDGF-alpha R) mRNA. In contrast, Pup V resembles smooth muscle cultures derived from uninjured adult rat arteries. It has an elongat ed morphology and proliferates poorly, in plasma-derived serum. This c lone expresses PDGF-alpha R mRNA, low levels of elastin and osteoponti n mRNAs, and lacks CYPIA1 and PDGF-B mRNAs. Pup IV and VI have most of the properties of pup I to III. We conclude that uncloned pup culture s are heterogeneous, but that the growth properties and gene expressio n pattern described for the uncloned culture is characteristic of indi vidual clones within the population.