Evi1 is specifically expressed in the distal tubule and duct of the Xenopus pronephros and plays a role in its formation.
The ecotropic viral integration site 1 (Evi1) and related MEL1 (MDS1/Evi1-like gene 1) genes are zinc finger oncogenic transcription factors involved in myeloid leukaemia. Here, we show that in Xenopus, Evi1 and MEL1 have partially overlapping restricted embryonic expression profiles. Within the pronephros, Evi1 and MEL1 are sequentially expressed within the distal tubule and duct compartments, Evi1 transcription being detected prior to any sign of pronephric morphogenesis. In the pronephros of zebrafish embryos, Evi1 expression is restricted to the posterior portion of the duct, the anterior portion having characteristics of proximal tubules. In the Xenopus pronephros, Evi1 expression is upregulated by retinoid signaling and repressed by overexpression of xWT1 and by Notch signaling. Overexpression of Evi1 from late neurula stage specifically inhibits the expression of proximal tubule and glomus pronephric markers. We show that the first zinc finger and CtBP interaction domains are required for this activity. Overexpression of a hormone-inducible Evi1-VP16 antimorphic fusion with activation at neurula stage disrupts distal tubule and duct formation and expands the expression of glomus markers. Although overexpression of this construct also causes in many embryos a reduction of proximal tubule markers, embryos with expanded and ectopic staining have been also observed. Together, these data indicate that Evi1 plays a role in the proximo-distal patterning of the pronephros and suggest that it may do so by functioning as a CtBP dependent repressor.
Laboratoire d'Embryologie Moléculaire, Université Libre de Bruxelles, Institut de Biologie et de Médecine Moléculaires (IBMM), rue des Profs. Jeener et Brachet 12, B-6041 Gosselies, Belgium.
Claude
C
Van Campenhout
Massimo
M
Nichane
Aline
A
Antoniou
Hélène
H
Pendeville
Odile J
OJ
Bronchain
Jean-Christophe
JC
Marine
Andre
A
Mazabraud
Marianne L
ML
Voz
Eric J
EJ
Bellefroid
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins; D018507:Gene Expression Regulation, Developmental; D007668:Kidney / Q000196:embryology / Q000254:growth & development*; D008565:Membrane Proteins; D009024:Morphogenesis; D016415:Sequence Alignment; D013963:Thyroid Hormones; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic; D015854:Up-Regulation; D029867:Xenopus Proteins / Q000235:genetics*; D014982:Xenopus laevis; D000097810:Thyroid Hormone-Binding Proteins
D002352:Carrier Proteins; D008565:Membrane Proteins; D013963:Thyroid Hormones; D014157:Transcription Factors; D029867:Xenopus Proteins; D000097810:Thyroid Hormone-Binding Proteins