Expression of multiple novel Wnt-1/int-1-related genes during fetal and adult mouse development.

The mammary tumor-associated proto-oncogene Wnt-1/int-1 encodes a secreted protein implicated in the regulation of neural development in vertebrates and segmental pattern in Drosophila. Using a PCR-based strategy, we isolated cDNAs encoding six novel, related proteins that are expressed in fetal mice. Predicted proteins are of similar molecular masses (38-42 kD) and share between 50% and 85% of amino acids. All contain a putative hydrophobic signal sequence, and comparative analysis reveals 83 absolutely conserved amino acid residues, including 21 cysteines. Transcripts were detected throughout fetal development by Northern blot analysis. Detailed examination of the expression of two of these genes by in situ hybridization revealed complex temporal and spatial patterns of transcription. All new Wnt family members are expressed in adult tissues, particularly in brain and lung. These data support the view that the Wnt-1/int-1 family constitutes a large family of signaling peptides with diverse roles in mouse development.