Expression of the gut-enriched Krüppel-like factor gene during development and intestinal tumorigenesis

Abstract

We examined the expression of GKLF (gut-enriched Krüppel-like factor), a recently identified zinc finger-containing transcription factor, in mice during development using the ribonuclease protection assay. In the adult, the level of GKLF transcript is abundant throughout the gastrointestinal tract. Between embryonic days 10 and 19 (E10 and E19) of development, the initial level of whole embryo GKLF transcript is low but begins to rise on E13 and peaks on E17. In the newborn, GKLF transcript level is higher in the colon than in the small intestine although the levels in both organs rise with increasing age. Expression of GKLF was also examined in the intestinal tract of the Min mouse, a model of intestinal tumorigenesis. The level of GKLF transcript is significantly decreased in the intestine of Min mice during a period of tumor formation when compared to age-matched control littermates. Our findings indicate that GKLF expression correlates with certain periods of gut development and is down-regulated during intestinal tumorigenesis, suggesting that GKLF may play a role in gut development and/or tumor formation.

Fig. 1

RPA of GKLF transcripts in the adult mouse gastrointestinal tract. Tissues were obtained from a 4 month-old wild-type C57BL/6J mouse. SI is small intestine. Twenty μg of total RNA from each tissue were hybridized to GKLF or β-actin riboprobe. Arrows indicate the protected fragments. Sizes of molecular mass markers are shown on the right. Lane 7 is a control containing yeast tRNA only and lane 8 is probe only.

Fig. 2

RPA of GKLF transcripts during fetal development. Total RNA was extracted from whole mouse embryos between E10 and E19 of development. Twenty μg from each day were used in the experiment to measure either GKLF or β-actin transcripts. As a comparison, 20 μg of RNA from tissues of a 4 week-old mouse were included in the experiment. Lanes 1, 16, and 17 contain yeast tRNA and lane 19 is probe only.

Fig. 3

RPA of GKLF transcripts in the intestines during postnatal development. RNA was extracted from whole small intestine or whole colon from mice at the stated days following birth (P4 to P210). Twenty μg of RNA were used in each lane.

Fig. 4

RPA of GKLF transcripts in the small intestine of wild-type and Min mice. RNA was extracted from whole small intestine from wild-type (+/+) or Min (Min/+) mice at the stated weeks after birth. Twenty μg were used in each lane.

Fig. 5

RPA of GKLF transcripts in the colon of wild-type and Min mice. Total RNA was extracted from whole colon of wild-type (+/+) or Min (Min/+) mice at the indicated time points after birth. In this experiment, 10 μg of RNA were used in each lane.