The pancreatic homeodomain transcription factor IDX1/IPF1 is expressed in neural cells during brain development.
Expression of the homeodomain transcription factor IDX1/IPF1 has been shown to be restricted to cells in the developing foregut that form the pancreatic primordium. In the adult, IDX1/IPF1 is expressed in the duodenum and pancreatic islets. The IDX1/IPF1 gene is required for pancreatic development, and in the human, heterozygous mutations have been linked to diabetes mellitus. In the present communication, we report that IDX1/IPF1 is expressed in discrete cells of the rat central nervous system during embryonic development. Using RT-PCR, IDX1/IPF1 mRNA was detected in neural precursor RC2.E10 cells, as well as in both forebrain and hindbrain of developing rats at embryonic day 15 (E15). The presence of IDX1/IPF1 protein was confirmed by Western immunoblotting. Immunohistochemical analyses of sagittal sections of E15 rats demonstrated the presence of scattered IDX1/IPF1-immunopositive cells in the forebrain. Finally, electrophoretic mobility shift assays using nuclear extracts from neural cells revealed the presence of IDX1/IPF1 bound to a putative homeodomain protein DNA-binding site present in the promoter of the glial fibrillary acidic protein gene. Our results suggest that IDX1/IPF1 may have previously unsuspected extrapancreatic functions during development of neural cells in the central nervous system.
Perez-Villamil
B
B
Reproductive Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
Schwartz
P T
PT
Vallejo
M
M
D000818:Animals; D001921:Brain / Q000196:embryology / Q000378:metabolism*; D004622:Embryo, Mammalian; D005865:Gestational Age; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007515:Islets of Langerhans / Q000502:physiology*; D009474:Neurons / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D016548:Prosencephalon / Q000196:embryology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015534:Trans-Activators / Q000235:genetics*
D005904:Glial Fibrillary Acidic Protein; D018398:Homeodomain Proteins; D015534:Trans-Activators; C084010:pancreatic and duodenal homeobox 1 protein