{{Short description|Protein-coding gene in the species Homo sapiens}} {{cs1 config|name-list-style=vanc|display-authors=6}} {{Infobox_gene}} '''Dickkopf-related protein 4''' is a protein in the Dickkopf family that in humans is encoded by the ''DKK4'' gene.<ref name="pmid10570958">{{cite journal | vauthors = Krupnik VE, Sharp JD, Jiang C, Robison K, Chickering TW, Amaravadi L, Brown DE, Guyot D, Mays G, Leiby K, Chang B, Duong T, Goodearl AD, Gearing DP, Sokol SY, McCarthy SA | title = Functional and structural diversity of the human Dickkopf gene family | journal = Gene | volume = 238 | issue = 2 | pages = 301–13 | date = October 1999 | pmid = 10570958 | doi = 10.1016/S0378-1119(99)00365-0 }}</ref>
==In cats==
In 2021, researchers at the Stanford University School of Medicine discovered that the gene, located on chromosome B1 of the cat genome,<ref name="ticked" /> is responsible for patterns on cats.<ref name="stanford news">{{cite web |last1=Armitage |first1=Hanae |title=Spots, stripes and blotches: Color patterns of cat fur tracked to a key gene |url=https://med.stanford.edu/news/all-news/2021/09/cat-fur-color-patterns.html |website=Stanford University School of Medicine |access-date=21 December 2021 |date=7 September 2021}}</ref> During embryonic development, the epidermis develops alternating thick and thin (in terms of depth, not width) regions, previously found to match the striped mackerel or blotchy patterns that would be expressed based on mutations in the embryos' ''Transmembrane aminopeptidase Q'' (''Taqpep'') gene. The genes ''DKK4'' and ''Wingless Inhibitory Factor 1'' (''WIF1'') both secrete Wnt signaling inhibitors, but in cells where both are upregulated, ''DKK4'' produces much more of its protein than WIF1. In ''DKK4''-positive cells, both Wnt signaling inhibitor and activator genes are upregulated, but inhibitor genes like ''DKK4'' secrete proteins with a larger area of effect. ''DKK4'' expression creates a molecular pre-pattern where the thick epidermal regions will develop, then gradually reduces as the embryo continues to develop. In embryos with the blotchy ''Taqpep'' mutation, ''DKK4'' was expressed less and in a broader pattern compared to embryos with the mackerel pattern version of the gene.<ref name="ticked">{{cite journal |last1=Kaelin |first1=Christopher B. |last2=McGowan |first2=Kelly A. |last3=Barsh |first3=Gregory S. |date=2021-09-07 |title=Developmental genetics of color pattern establishment in cats |journal=Nature Communications |volume=12 |issue=5127 |page=5127 |doi=10.1038/s41467-021-25348-2 |pmid=34493721 |pmc=8423757 |bibcode=2021NatCo..12.5127K }}</ref>
''DKK4'' was also examined in specifically Abyssinian cats, which are known for their “ticked” fur with bands of colors on each hair. Two variants, or alleles, of ''DKK4'', p.Ala18Val and p.Cys63Tyr, were discovered in cats with obscured tabby markings. In some other breeds and non-breeds of cats, the presence of p.Ala18Val also correlated with the Ticked phenotype, while other variants correlated with the Non-Ticked phenotype. These variants caused loss of function of the ''DKK4'' gene<ref name="ticked" /> and smaller, more tightly packed dark areas.<ref name="stanford news" />
== References == {{reflist}}
{{gene-8-stub}}