LIN28 is thought to regulate the self-renewal of stem cells. In Caenorhabditis elegans, there is only one Lin28 gene that is expressed and in vertebrates, there are two paralogs present, Lin28a and Lin28b. In nematodes, the LIN28 homolog lin-28 is a heterochronic gene that determines the onset of early larval stages of developmental events in C. elegans, by regulating the self-renewal of nematode stem cells in the skin (called seam cells) and vulva (called VPCs) during development.[8] In mice, LIN28 is highly expressed in mouse embryonic stem cells and during early embryogenesis.[9]
LIN28 is highly expressed in human embryonic stem cells[10] and can enhance the efficiency of the formation of induced pluripotent stem (iPS) cells from human fibroblasts.[11]
LIN28 can regulate glucose homeostasis in mammals by increasing insulin-PI3K-mTOR signaling and insulin sensitivity, thereby promoting resistance to high fat diet-induced obesity and type 2 diabetes.[14] Aberrant expression of LIN28 has been seen to regulate aerobic glycolysis to facilitate cancer proliferation
Tissue regeneration
Mice genetically altered to produce LIN28 during their lifespan showed improved hair growth.[15] and healthy tissue regeneration on added puncture wounds[15] in later life stages.[15] While the mice could regenerate limbs, they could not repair damaged heart tissue. Appropriate drugs replicated the regeneration in unaltered mice, using the same metabolic paths. The drugs increased the subjects' metabolic rates, evidently causing the body to heal at higher rates. The effects of Lin28a activation faded with age.[15][16]
Structure
Models of Lin28/let-7 complexes obtained through X-ray crystallography and NMR reveal that two folded domains of Lin28 recognize two distinct RNA regions[17][18]. The domains are sufficient for inhibition of let-7 in vivo.[6][19]
Applications
LIN28 is a marker of undifferentiated human embryonic stem cells[10] and has been used to enhance the efficiency of the formation of iPS cells from human fibroblasts.[11]
References
↑Moss EG, Tang L (Jun 2003). "Conservation of the heterochronic regulator Lin-28, its developmental expression and microRNA complementary sites". Developmental Biology. 258 (2): 432–42. doi:10.1016/S0012-1606(03)00126-X. PMID12798299.
↑Tsialikas J, Romer-Seibert J (Jul 2015). "LIN28: roles and regulation in development and beyond". Development. 142 (14): 2397–404. doi:10.1242/dev.117580. PMID26199409.
↑ 6.06.1Ali PS, Ghoshdastider U, Hoffmann J, Brutschy B, Filipek S (Nov 2012). "Recognition of the let-7g miRNA precursor by human Lin28B". FEBS Letters. 586 (22): 3986–90. doi:10.1016/j.febslet.2012.09.034. PMID23063642.
↑Balzer E, Moss EG (2007). "Localization of the developmental timing regulator Lin28 to mRNP complexes, P-bodies and stress granules". RNA Biology. 4 (1): 16–25. doi:10.4161/rna.4.1.4364. PMID17617744.
↑Moss EG, Lee RC, Ambros V (Mar 1997). "The cold shock domain protein LIN-28 controls developmental timing in C. elegans and is regulated by the lin-4 RNA". Cell. 88 (5): 637–46. doi:10.1016/s0092-8674(00)81906-6. PMID9054503.
↑Yang DH, Moss EG (Dec 2003). "Temporally regulated expression of Lin-28 in diverse tissues of the developing mouse". Gene Expression Patterns. 3 (6): 719–26. doi:10.1016/s1567-133x(03)00140-6. PMID14643679.
↑ 10.010.1Richards M, Tan SP, Tan JH, Chan WK, Bongso A (2004). "The transcriptome profile of human embryonic stem cells as defined by SAGE". Stem Cells. 22 (1): 51–64. doi:10.1634/stemcells.22-1-51. PMID14688391.
↑ 11.011.1Yu J, Vodyanik MA, Smuga-Otto K, Antosiewicz-Bourget J, Frane JL, Tian S, Nie J, Jonsdottir GA, Ruotti V, Stewart R, Slukvin II, Thomson JA (Dec 2007). "Induced pluripotent stem cell lines derived from human somatic cells". Science. 318 (5858): 1917–20. doi:10.1126/science.1151526. PMID18029452.
↑Nam, Yunsun; Chen, Casandra; Gregory, Richard I.; Chou, James J.; Sliz, Piotr (November 2011). "Molecular Basis for Interaction of let-7 MicroRNAs with Lin28". Cell. 147 (5): 1080–1091. doi:10.1016/j.cell.2011.10.020.
↑Loughlin, Fionna E; Gebert, Luca F R; Towbin, Harry; Brunschweiger, Andreas; Hall, Jonathan; Allain, Frédéric H-T (11 December 2011). "Structural basis of pre-let-7 miRNA recognition by the zinc knuckles of pluripotency factor Lin28". Nature Structural & Molecular Biology. 19 (1): 84–89. doi:10.1038/nsmb.2202.
Richards M, Tan SP, Tan JH, Chan WK, Bongso A (2004). "The transcriptome profile of human embryonic stem cells as defined by SAGE". Stem Cells. 22 (1): 51–64. doi:10.1634/stemcells.22-1-51. PMID14688391.
Gerecht-Nir S, Dazard JE, Golan-Mashiach M, Osenberg S, Botvinnik A, Amariglio N, Domany E, Rechavi G, Givol D, Itskovitz-Eldor J (Feb 2005). "Vascular gene expression and phenotypic correlation during differentiation of human embryonic stem cells". Developmental Dynamics. 232 (2): 487–97. doi:10.1002/dvdy.20247. PMID15614775.
Lee YS, Kim HK, Chung S, Kim KS, Dutta A (Apr 2005). "Depletion of human micro-RNA miR-125b reveals that it is critical for the proliferation of differentiated cells but not for the down-regulation of putative targets during differentiation". The Journal of Biological Chemistry. 280 (17): 16635–41. doi:10.1074/jbc.M412247200. PMID15722555.