Developmental expression of Eph and ephrin family genes in mammalian small intestine.
BACKGROUND
Eph receptor tyrosine kinases EphB2 and EphB3, and ephrin-B1 ligand play a critical role in regulating small intestinal epithelial cell migration. Although well studied in developing brain, the expression pattern of Ephs/ephrins has not been delineated in the developing small intestine.


OBJECTIVE
To examine the gene expression of all known members of Ephs/ephrins during development of mouse small intestine.


METHODS
We examined the expression of 21 A- and B-Ephs/ephrins in mouse small intestine or the Caco-2 cell line using reverse-transcription polymerase chain reaction (RT-PCR), quantitative (q)RT-PCR, and immunohistochemical analyses. EphB2-expressing cells from isolated crypts were detected by immunofluorescence and fluorescence-activated cell sorting (FACS) analyses.


RESULTS
With the exception of EphA5, all family members were expressed throughout the intestine at all ages examined. Most were uniformly expressed. In contrast, levels of EphA4, EphA8, EphB4, and ephrin-B2 messenger RNA (mRNA) were highest during early fetal development and declined with age. At E15, EphB2 and EphB4 proteins were diffusely expressed in proliferating stratified intestinal epithelial cells. By E18, the proteins had become localized to cell membranes of columnar epithelial cells within intervillus regions, and later were expressed on epithelial cell membranes in adult crypts. EphB2-expressing cells can be specifically isolated from crypt cell fractions.


CONCLUSIONS
The current study represents the first analysis of Ephs/ephrins during intestinal development. The elevated expression of EphA4, EphA8, EphB4, and ephrin-B2 during the fetal period of intestinal morphogenesis suggests an important role in development. Continued intestinal expression of other family members implicates a role in differentiation.
Islam
Shabana
S
Gastrointestinal Cell and Molecular Biology Laboratories, Division of Gastroenterology and Nutrition, Children's Hospital Boston, and Department of Pediatrics, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
Loizides
Anthony M
AM
Fialkovich
John J
JJ
Grand
Richard J
RJ
Montgomery
Robert K
RK
D000367:Age Factors; D000818:Animals; D018938:Caco-2 Cells; D002454:Cell Differentiation; D002469:Cell Separation; D036342:Ephrins / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D006801:Humans; D007150:Immunohistochemistry; D007421:Intestine, Small / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009024:Morphogenesis; D012333:RNA, Messenger / Q000378:metabolism; D036081:Receptors, Eph Family / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D036342:Ephrins; D012333:RNA, Messenger; D036081:Receptors, Eph Family