DLK1

DLK1, also known as Delta-like 1 homolog or preadipocyte factor 1 (Pref-1), is a protein-coding gene in humans. It is located in the imprinted DLK1-DIO3 region on chromosome 14q32 and is expressed from the paternal allele while the region is subject to maternal imprinting. The DLK1 gene encodes a type I transmembrane protein related to the Notch/Delta/Serrate family, but it functions as a non-canonical Notch ligand that lacks the typical DSL domain. The extracellular portion contains EGF-like repeats and can be released from the cell surface as a soluble form.

In development and metabolism, DLK1 serves as a regulator of cell differentiation. In adipose tissue, Pref-1 is highly expressed in preadipocytes and acts as a potent inhibitor of adipogenesis, delaying differentiation by repressing key adipogenic transcription factors. Expression generally declines as adipocytes mature. Beyond adipogenesis, DLK1 is implicated in fetal development and tissue morphogenesis, with expression patterns in several developing organs and in stem cell-rich niches.

Clinical and research interest in DLK1 centers on its roles in disease and physiology. Aberrant DLK1 expression or regulation has been observed in various cancers and in metabolic states, and circulating DLK1 can be detected as a soluble protein. Ongoing studies examine its potential as a biomarker and as a component of signaling networks that influence cell fate decisions.