Increased c/ebp in fetal rat small intestine precedes initiation of
differentiation marker mrna synthesis.
Montgomery, Robert K., Edmond H. H. M. Rings, John F. Thompson,
Carelle C. Schuijt, Kathleen M. Aras, Vera J. M. Wielenga, M. J.
Christine Kothe, Hans A. B[umlaut]uller, and Richard J. Grand.
Division of Pediatric Gastroenterology and Nutrition, Boston
Floating Hospital for Children, New England Medical Center and Tufts
University School of Medicine, Boston, MA and Division of Pediatric
Gastroenterology and Nutrition, Academic Medical Center, Amsterdam,
The Netherlands.
APStracts 3:0212G, 1996.
Morphogenesis, initiation of differentiation marker gene expression,
and their correlation with C/EBP expression were analyzed in the
developing fetal rat small intestine. Expression of mRNAs for LPH,
IALP, CPS1, and three isoforms of C/EBP was simultaneously determined
by Northern blot analysis from 15 to 19 days of gestation. At 17 days
of gestation, prior to villus formation as demonstrated by light and
electron microscopy, only CPS and C/EBP[alpha],[beta], and [delta]
expression could clearly be detected. Both LPH and IALP mRNA were
definitely detectable in proximal and middle intestine on day 18, as
soon as the stratified epithelium of the early intestine had been
transformed into a single layer of columnar epithelium lining villi.
This distribution was confirmed by in situ hybridization for LPH
mRNA. During the period of transformation when the columnar
epithelium and villi were forming, no LPH or IALP mRNA was detectable
in the immature distal third of the fetal intestine. Preceding villus
morphogenesis, immunostaining demonstrated nuclear localization of
C/EBP[alpha] protein in intestinal epithelial cells, with continued
expression in all enterocytes through 19 days of gestation. Enhanced
expression of C/EBP[alpha] mRNA and protein began 24 hours prior to
the initiation of the differentiation markers, suggesting that it may
play a role in regulation of fetal intestinal differentiation.
Received 2 February 1996; accepted in final form 28 September
1996.
APS Manuscript Number G50-6.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 November 1996