title: Patterns of gene expression along the crypt-villus axis in mouse jejunal epithelium.
abstract: BACKGROUND
  There is considerable interest in gene expression along the crypt-villus axis of the small intestinal epithelium, particularly in the identification of genes expressed in intestinal crypts.
  
  
  METHODS
  In an attempt to identify crypt-expressed genes, single-stranded cDNA made from normal mouse jejunal epithelium was used in subtractive hybridization against single-stranded cDNA from epithelium from which crypt cells were depleted by 2,000 rads of gamma irradiation. Partial DNA sequence and in situ hybridization of 72 resulting clones were determined.
  
  
  RESULTS
  The sequence of 45 clones matched previously published genes. Gene expression patterns fell into three categories: expression throughout the crypt-villus axis, expression restricted to the villus, and expression restricted to the crypt. Clones in the first two categories could be further divided into three subgroups: those with uniform expression, those with an increasing gradient of expression, and those with a decreasing gradient of expression along the crypt-villus axis. Twenty two clones showed a stronger expression in crypt and lower villus cells, four of these were differentially localized to the crypt. Two of the crypt localized clones were uniformly expressed throughout the crypt, expression of one was stronger in the lower crypt, and expression of the remaining clone was enhanced Paneth cells. We report the full-length cDNA sequence of the Paneth-cell-enhanced clone.
  
  
  CONCLUSIONS
  The screen isolated crypt-expressed genes that may prove useful tools in the study of crypt biology. In a companion report, we characterize one of the crypt clones.
authors.affiliation: Department of Anatomy and Cell Biology, University of Toronto, Ontario, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Cheng
authors.forename: M
authors.initials: M
authors.lastname: Bjerknes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002469:Cell Separation; D017931:DNA Primers; D018076:DNA, Complementary; D004848:Epithelium / Q000033:anatomy & histology / Q000502:physiology; D015870:Gene Expression / Q000235:genetics*; D015723:Gene Library; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D017403:In Situ Hybridization; D007583:Jejunum / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008858:Microscopy, Phase-Contrast; D000226:Mitochondrial ADP, ATP Translocases / Q000378:metabolism; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D014157:Transcription Factors
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D014157:Transcription Factors; D000226:Mitochondrial ADP, ATP Translocases; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases