Gene expression in the embryonic Xenopus liver.
In recent years, significant progress has been made in uncovering the molecular basis of endoderm specification in Xenopus. Much less is understood, however, about endodermal patterning and how endoderm-derived organs such as the liver are formed. Progress has been hampered by the lack of good molecular markers of presumptive liver tissue. Here, we have examined the embryonic expression of a number of marker genes during liver organogenesis, including the transcription factors hex, sox17alpha, and hnf3beta, as well as a number of proteins specific to the adult liver. Interestingly, sox17alpha appears to specifically mark the gall bladder precursors. At 7 days of development expression of the liver differentiation markers albumin, alpha1-microglobulin/bikunin precursor, fibrinogen, transferrin and transthyretin is restricted to the differentiating liver bud. Surprisingly, however, at 3 days of development most of these genes have a more widespread endodermal expression pattern. In addition to expression in the undifferentiated liver bud they were expressed extensively throughout the presumptive intestinal tissue, which may reflect some general feature of how the hepatic gene program is developmentally regulated.
Zorn
A M
AM
Wellcome/CRC Institute of Cancer and Developmental Biology, Tennis Court Road, Cambridge, CB2 1QR, UK. amz@mole.bio.cam.ac.uk
Mason
J
J
D000418:Albumins / Q000096:biosynthesis; D000818:Animals; D002454:Cell Differentiation; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D005340:Fibrinogen / Q000096:biosynthesis; D015870:Gene Expression; D051542:Hepatocyte Nuclear Factor 3-beta; D006609:High Mobility Group Proteins; D018398:Homeodomain Proteins / Q000096:biosynthesis; D017403:In Situ Hybridization; D008099:Liver / Q000196:embryology* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D008954:Models, Biological; D009687:Nuclear Proteins / Q000096:biosynthesis; D011228:Prealbumin / Q000096:biosynthesis; D014176:Protein Biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055760:SOXF Transcription Factors; D014157:Transcription Factors; D014168:Transferrin / Q000096:biosynthesis; D014360:Trypsin Inhibitor, Kunitz Soybean; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins
D000418:Albumins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D018398:Homeodomain Proteins; D008562:Membrane Glycoproteins; D009687:Nuclear Proteins; D011228:Prealbumin; D055760:SOXF Transcription Factors; C109148:SPINT2 protein, human; D014157:Transcription Factors; D014168:Transferrin; D029867:Xenopus Proteins; C513078:hhex protein, Xenopus; C491602:sox17a protein, Xenopus; C491601:sox17b.1 protein, Xenopus; D051542:Hepatocyte Nuclear Factor 3-beta; D005340:Fibrinogen; D014360:Trypsin Inhibitor, Kunitz Soybean