Send to

Choose Destination
EMBO J. 1994 Mar 1;13(5):1145-56.

IDX-1: a new homeodomain transcription factor expressed in rat pancreatic islets and duodenum that transactivates the somatostatin gene.

Author information

Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Boston.


We describe the cloning from a rat islet somatostatin-producing cell line of a 1.4 kb cDNA encoding a new homeoprotein, IDX-1 (islet/duodenum homeobox-1), with close sequence similarity to the Drosophila melanogaster homeobox protein Antennapedia (Antp) and the Xenopus laevis endoderm-specific homeoprotein XlHbox8. Analyses of IDX-1 mRNA and protein in rat tissues show that IDX-1 is expressed in pancreatic islets and ducts and in the duodenum. In electrophoretic mobility shift assays IDX-1 binds to three sites in the 5' flanking region of the rat somatostatin gene. In co-transfection experiments IDX-1 transactivates reporter constructs containing somatostatin promoter sequences, and mutation of the IDX-1 binding sites attenuates transactivation. Reverse transcription-polymerase chain reaction of islet RNA using degenerate amplimers for mRNAs encoding homeoproteins indicates that IDX-1 is the most abundant of 12 different Antp-like homeodomain mRNAs expressed in adult rat islets. The pattern of expression, relative abundance and transcriptional regulatory activity suggests that IDX-1 may be involved in the regulation of islet hormone genes and in cellular differentiation in the endocrine pancreas and the duodenum.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center