Basic Information
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Description
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- Wnt‑16 is a 40 kDa protein within the Wnt family of secreted, highly conserved, cysteine‑rich, palmitoylated cell signaling glycoproteins that play important roles in vertebrate developmental pattern formation, cell fate decision, axon guidance, and tumor formation. Wnt‑16a and Wnt‑16b isoforms in humans differ in the signal sequence and the first two amino acids (aa) of the mature protein.
- Wnt‑16b is the more conserved isoform and is widely expressed, while Wnt‑16a is expressed mainly in the human pancreas. Mature human Wnt‑16b shares 92%, 93%, and 95% aa sequence identity with mouse/rat, rabbit/porcine/equine, and bovine Wnt‑16, respectively. Wnt‑16 expression is detected on uterine stroma adjacent to the luminal epithelium during implantation. It is up‑regulated during the first embryonic lymphoid progenitor differentiation. Congenital heart defects correlate with elevated Wnt‑16 in mouse embryos and human amniotic fluid. Low cortical bone thickness and bone mineral density correlate with deletion of Wnt‑16 in mice and a Wnt‑16 missense SNP in humans.
- Wnt‑16 is over‑expressed in cells undergoing replicative senescence, and is up‑regulated in articular cartilage by injury and osteoarthritis. Wnt‑16b expression in skin is up‑regulated in human basal cell carcinomas, enhancing cell survival. Its expression is also up‑regulated by DNA damage (radiation and chemotherapy) in stroma surrounding prostate tumors, causing enhanced survival and treatment resistance in the tumor cells.
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Targeting strategy
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Gene targeting strategy for B-hWNT16 mice.
The exons 1-4 of mouse Wnt16 gene that encode signal peptide, extracellular domain and transmembrane domain is replaced by human counterparts in B-hWNT16 mice. The genomic region of mouse Wnt16 gene that encodes cytoplasmic portion is retained. The promoter, 5’UTR and 3’UTR region of the mouse gene are replaced by human counterparts. The chimeric WNT16 expression is driven by endogenous human WNT16 promoter, while mouse Wnt16 gene transcription and translation will be disrupted.
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mRNA expression analysis
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Strain specific analysis of WNT16 mRNA expression in wild-type C57BL/6 mice and B-hWNT16 mice by RT-PCR. Brain RNA were isolated from wild-type C57BL/6 mice (+/+) and homozygous B-hWNT16 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human WNT16 primers. Mouse Wnt16 mRNA was detectable in wild-type C57BL/6 mice and homozygous B-hWNT16 mice. Human WNT16 mRNA was detectable only in homozygous B-hWNT16 mice but not in wild-type mice.
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Protein expression analysis
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Western blot analysis of WNT16 protein expression in homozygous B-hWNT16 mice. Various tissue lysates were collected from wild-type C57BL/6N mice (+/+) and homozygous B-hWNT16 mice(H/H), and then analyzed by western blot with anti-WNT16 antibody (Abcam ab109437). 40 μg total proteins were loaded for western blotting analysis. WNT16 was detected in ovary, kidney, brain, stomach and skin in wild-type mice and homozygous B-hWNT16 mice, as the antibody is cross-recognize both human and mouse WNT16.
