288
LAURI SAXEN ET AL.
anodal LDH pattern were dissociated and grown in vitro as monolayers
through three passages, all signs of differentiation as measured by the
LDH zymogram were lost. Comparable results with kidney-specific antigen have been reported by Okada (1965a,b,c). The antigen was detectable only as long as the tubules remained organized. These findings are in
accordance with the experience that cells from the organs, when dissociated and grown in cell cultures, lose many markers of their phenotype, although several exceptions to this rule have also been reported
(Konigsberg, 1963; Coon and Cahn, 1966).
V. Concluding Remarks
The review presents data obtained in experiments with an experimental
model system for differentiation, the induction of secretory kidney
tubules. A variety of markers for differentiation at the levels of nucleic
acid synthesis, protein synthesis, and morphology were followed. The
results are summarized and temporally correlated in Fig. 21. Evidence is
presented suggesting that in this model system some of the biochemical
markers of differentiation and the structural organization of the tubules
are in causal relationship and controlled by inductive tissue interactions
between heterotypic and homotypic tissue components.
Acknowledgments
The authors' experimental work reported in this review has been supported by the
following grants and foundations: PHS research grant C-5347 from the National
Cancer Institute, U.S. Public Health Service, the Damon Runyon Memorial
Foundation grant DRG 938, the Sigrid Juselius Foundation, and the Finnish
National Research Council for Medical Sciences.
References
Appella, E., and Markert, C. L. (1961). Dissociation of lactate dehydrogenase into
subunits with guanine hydrochloride. Biochem. Biophys. Res. Commun. 6, 171176.
Auerbach, R. (1960a). Morphogenetic interactions in the development of the mouse
thymus gland. Develop. Biol. 2, 271-284.
Auerbach, R. (1960b). The organization and reorganization of embryonic cells. In
"Self-organizing Systems," pp. 101-107. Pergamon Press, Oxford.
Ben-Or, S., and Bell, E. (1965). Skin antigens in the chick embryo in relation to
other developmental events. Develop. Biol. 11, 184-201.
Boyer, S. H., Fainer, D. C, and Watson-Williams, E. J. (1963). Lactate dehydrogenase variant from human blood: Evidence for molecular subunits. Science 141,
642-643.
Brachet, J. (1962). Nucleic acids in development. J. Cellular Comp. Physiol. 60, 1-18.
LAURI SAXEN ET AL.
anodal LDH pattern were dissociated and grown in vitro as monolayers
through three passages, all signs of differentiation as measured by the
LDH zymogram were lost. Comparable results with kidney-specific antigen have been reported by Okada (1965a,b,c). The antigen was detectable only as long as the tubules remained organized. These findings are in
accordance with the experience that cells from the organs, when dissociated and grown in cell cultures, lose many markers of their phenotype, although several exceptions to this rule have also been reported
(Konigsberg, 1963; Coon and Cahn, 1966).
V. Concluding Remarks
The review presents data obtained in experiments with an experimental
model system for differentiation, the induction of secretory kidney
tubules. A variety of markers for differentiation at the levels of nucleic
acid synthesis, protein synthesis, and morphology were followed. The
results are summarized and temporally correlated in Fig. 21. Evidence is
presented suggesting that in this model system some of the biochemical
markers of differentiation and the structural organization of the tubules
are in causal relationship and controlled by inductive tissue interactions
between heterotypic and homotypic tissue components.
Acknowledgments
The authors' experimental work reported in this review has been supported by the
following grants and foundations: PHS research grant C-5347 from the National
Cancer Institute, U.S. Public Health Service, the Damon Runyon Memorial
Foundation grant DRG 938, the Sigrid Juselius Foundation, and the Finnish
National Research Council for Medical Sciences.
References
Appella, E., and Markert, C. L. (1961). Dissociation of lactate dehydrogenase into
subunits with guanine hydrochloride. Biochem. Biophys. Res. Commun. 6, 171176.
Auerbach, R. (1960a). Morphogenetic interactions in the development of the mouse
thymus gland. Develop. Biol. 2, 271-284.
Auerbach, R. (1960b). The organization and reorganization of embryonic cells. In
"Self-organizing Systems," pp. 101-107. Pergamon Press, Oxford.
Ben-Or, S., and Bell, E. (1965). Skin antigens in the chick embryo in relation to
other developmental events. Develop. Biol. 11, 184-201.
Boyer, S. H., Fainer, D. C, and Watson-Williams, E. J. (1963). Lactate dehydrogenase variant from human blood: Evidence for molecular subunits. Science 141,
642-643.
Brachet, J. (1962). Nucleic acids in development. J. Cellular Comp. Physiol. 60, 1-18.