Cdx1 and cdx2 expression during intestinal development.
OBJECTIVE
The intestine-specific transcription factors Cdx1 and Cdx2 are candidate genes for directing intestinal development, differentiation, and maintenance of the intestinal phenotype. This study focused on the complex patterns of expression of Cdx1 and Cdx2 during mouse gastrointestinal development.


METHODS
Embryonic and postnatal mouse tissues were analyzed by immunohistochemistry to determine protein expression of Cdx1 and Cdx2 in the developing intestinal tract.


RESULTS
Cdx2 protein expression was observed at 9. 5 postcoitum (pc), whereas weak expression of Cdx1 protein was first seen at 12.5 pc in the distal developing intestine (hindgut). Expression of Cdx1 increased from 13.5 to 14.5 pc during the endoderm/epithelial transition with predominately distal expression. In contrast to Cdx1, there was intense expression of Cdx2 in all but the distal portions of the developing intestine. Cdx2 expression remained low in the distal colon throughout postnatal development. A gradient of expression formed in the crypt-villus axis, with Cdx1 primarily in the crypt and Cdx2 primarily in the villus.


CONCLUSIONS
Direct comparison of the patterns of Cdx1 and Cdx2 protein expression during development as performed in this study provides new insights into their potential functional roles. The relative expression of Cdx1 to Cdx2 protein may be important in the anterior to posterior patterning of the intestinal epithelium and in defining patterns of proliferation and differentiation along the crypt-villus axis.
Silberg
D G
DG
Division of Gastroenterology, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. silberg@mail.med.upenn.edu
Swain
G P
GP
Suh
E R
ER
Traber
P G
PG
D016475:3T3 Cells; D000375:Aging; D000818:Animals; D030161:Avian Proteins; D000071616:CDX2 Transcription Factor; D002460:Cell Line; D003106:Colon / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D005314:Embryonic and Fetal Development; D004707:Endoderm / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007413:Intestinal Mucosa / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D007421:Intestine, Small / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism; D015534:Trans-Activators
D030161:Avian Proteins; C491273:CDX1 protein, human; D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; C491272:Cdx1 protein, mouse; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D015534:Trans-Activators