Differentiational regulation and phosphorylation of the fatty acid-binding protein from rat mammary epithelial cells

An in situ hybridization technique using a [35S]-labeled oligonucleotide probe was employed, in combination with immunohistochemistry and autoradiography, to examine gene expression for hepatic fatty acid binding protein (FABP) in the jejunal epithelia from both fed and fasted rats. In rats fed ad libitum, immunoreactivity and mRNA signal for FABP were localized to the absorptive epithelial cells lining the villus, whereas they were absent in the crypt epithelial cells. The level of FABP mRNA was relatively low in the tip of the villus, although FABP immunoreactivity remained high in this area. Animals fasted for 3 days exhibited a downward shift of the lower boundary of the FABP-expressing cell population into the middle portion of the crypt, in terms of the immunoreactivity and the mRNA signal. The proliferative cell compartment of the crypt, as revealed by [3H]-TdR incorporation, showed no substantial change in size between the fed and fasted states. The present results provided evidence that (a) during the differentiation and upward migration of the absorptive epithelial cells, the expression of FABP gene begins at the crypt-villus junction and declines before the cells reach the villus tip, and (b) fasting induces an earlier expression of the FABP gene in the maturing crypt epithelial cells.

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Expression of intestinal fatty acid binding protein in intestinal epithelial cell lines, hBRIE 380 cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1994.267.4.g730 ◽

1994 ◽

Vol 267 (4) ◽

pp. G730-G743 ◽

Cited By ~ 2

Author(s):

G. Hallden ◽

E. L. Holehouse ◽

X. Dong ◽

G. W. Aponte

Keyword(s):

Fatty Acid ◽

Cell Differentiation ◽

Epithelial Cells ◽

Fatty Acid Binding Protein ◽

Intestinal Epithelial Cells ◽

Binding Protein ◽

Intestinal Cell ◽

Intestinal Epithelial ◽

Fatty Acid Binding ◽

Acid Binding Protein

Intestinal fatty acid binding protein (I-FABP) is a cytosolic protein present only in differentiated intestinal epithelial cells. Here we report on an intestinal cell culture system expressing I-FABP during cell differentiation and the modulation of expression by extracellular factors. An I-FABP-expressing cell line (hBRIE 380i) was generated from Berkeley rat intestinal epithelial cells (hBRIE 380). Time- and substratum-dependent changes in I-FABP mRNA expression were paralleled by changes in protein levels. Induction of I-FABP levels observed on collagen type I gels in the presence of limiting serum was prevented by insulin. When cells were grown on collagen gels containing fibronectin and laminin, a stimulation of ultrastructural characteristics of cell differentiation was observed with no further induction of I-FABP expression. The data show that I-FABP expression is limited to a differentiated population of hBRIE 380i cells and that the expression can be regulated by factors present in the extracellular matrix as well as involved in regulation of replication or metabolic state of the cell.

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