CHIMERIC-TRANSGENIC MICE REPRESENT A POWERFUL TOOL FOR STUDYING HOW THE PROLIFERATION AND DIFFERENTIATION PROGRAMS OF INTESTINAL EPITHELIAL-CELL LINEAGES ARE REGULATED
Ml. Hermiston et al., CHIMERIC-TRANSGENIC MICE REPRESENT A POWERFUL TOOL FOR STUDYING HOW THE PROLIFERATION AND DIFFERENTIATION PROGRAMS OF INTESTINAL EPITHELIAL-CELL LINEAGES ARE REGULATED, Proceedings of the National Academy of Sciences of the United Statesof America, 90(19), 1993, pp. 8866-8870
An in vivo system has been developed for examining the effects of wild
-type or mutant proteins on cell fate determination in the mouse intes
tinal epithelium or on the proliferation and differentiation programs
of its component epithelial lineages. This system takes advantage of t
he fact that at the conclusion of gut morphogenesis, each intestinal c
rypt is composed of a monoclonal population of cells descended from a
single active multipotent stem cell, each villus is supplied by severa
l monoclonal crypts, and the four principal cell types of the intestin
al epithelium differentiate during a rapid, geographically well-organi
zed migration along the crypt-to-villus axis. Embryonic stem (ES) cell
s (129/Sv origin) are initially transfected with recombinant DNAs cons
isting of a reporter of interest linked to transcriptional regulatory
elements that control the cell lineage-specific, differentiation-depen
dent, and axial patterns of expression of fatty acid binding protein g
enes in the gut. Stably transfected ES cells are subsequently introduc
ed into host C57BL/6 blastocysts to generate chimeric-transgenic mice.
At the borders of ES cell-derived and host blastocyst-derived epithel
ium, intestinal villi are found that are supplied by both ES cell- and
host blastocyst-derived crypts. These villi can be rapidly identified
in fixed whole-mount preparations of intestine using the alpha-L-fuco
se-specific Ulex europaeus agglutinin type I (UEA-I) lectin. They appe
ar striped because UEA-I recognizes a cell-surface carbohydrate polymo
rphism between the inbred strains used to generate the chimeric animal
s. The strength of this system derives from the fact that two gut epit
helial populations can be compared and contrasted that occupy virtuall
y identical positions along the crypt-to-villus and duodenal-to-coloni
c axes within the same animal and differ only by the presence or absen
ce of a single gene product. The band of blastocyst-derived epithelium
in these striped, polyclonal villi can be used as an internal control
to assess the biological effect of the transfected gene product produ
ced in the adjacent stripe of ES-derived cells. The system can be used
for either gain-of-function or loss-of-function experiments.