About LIN Protein:
LIN28 encodes an RNA-binding protein, which binds to and promotes translation of the IGF-2 (insulin-like growth factor 2) mRNA. Lin28 binds to the let-7 pre-microRNA and prevents the mature let-7 microRNA from being produced in mouse embryonic stem cells. LIN protein is found in ribosomes, P-bodies, and stress granules in pluripotent embryonal carcinoma cells.
LIN Protein Structure
X-ray crystallography and NMR models of Lin28/let-7 complexes show that two folded domains of Lin28 recognise two distinct RNA regions. In vivo, the domains are sufficient to inhibit let-7. LIN28 is a marker of undifferentiated human embryonic stem cells and has been used to improve the efficiency of iPS cell formation from human fibroblasts.
LIN Protein Function
The functions of LIN28 include:
●Stem Cell Expressions - LIN28 is thought to regulate stem cell self-renewal. Caenorhabditis elegans has only one Lin28 gene expressed, whereas vertebrates have two paralogs, Lin28a and Lin28b. The LIN28 homolog lin-28 is a heterochronic gene in C. elegans that regulates the self-renewal of nematode stem cells in the skin (called seam cells) and vulva (called VPCs) during development.
●Puberty - Overexpression of LIN28 in mice, can result in gigantism, and a delay in puberty onset, consistent with human genome-wide association studies that show polymorphisms in the human LIN28B gene are associated with human height and puberty timing. Precocious puberty is linked to LIN28B mutations.
●Tissue Regeneration - Mice genetically modified to produce LIN28 throughout their lives had better hair growth and healthy tissue regeneration. Using the same metabolic pathways, appropriate drugs replicated regeneration in unaltered mice. The drugs increased the subjects' metabolic rates, causing the body to heal at a faster rate. With age, the effects of Lin28a activation faded.