CONTRIBUTIONS TO SOMATIC AND GERMLINE LINEAGES OF CHICKEN BLASTODERMAL CELLS MAINTAINED IN CULTURE

Chicken blastodermal cells were cultured for 48 hr as explanted intact embryos, as dispersed cells in a monolayer, or with a confluent layer df mouse fibroblasts. The cells were then dispersed and injected into stage X (E-G&K) recipient embryos that were exposed to 600 rads of ir radiation from a Co-60 source. Regardless of the conditions in which t he cells were cultured; chimeras with contributions to both somatic ti ssues and the germline were observed. When blastodermal cells were coc ultured with mouse embryonic fibroblasts, significantly more somatic c himeras were observed and the proportion of feather follicles derived from donor cells was increased relative to that observed following the injection of cells derived from explanted embryos or monolayer cultur es. Culture of blastodermal cells in any of the systems, however, yiel ded fewer chimeras that exhibited reduced contributions to somatic tis sues in comparison to the frequency and extent of somatic chimerism ob served following injection of freshly prepared cells. Contributions to the germline were observed at an equal frequency regardless of the co nditions of culture, but were significantly reduced in comparison to t he frequency and rate of germline transmission following injection of cells obtained directly from stage X (E-G&K) embryos. These data demon strate that some cells retain the ability to contribute to germline an d somatic tissues after 48 hr in culture and that the ability to contr ibute to the somatic and germline lineages is not retained equally. (C ) 1996 Wiley-Liss, Inc.