Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.10.3.1 (tyrosinase)
 9,065 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proopiomelanocortin (POMC), the precursor for melanotropic, corticotropic, and opioid peptides such as alpha-melanocyte-stimulating hormone (alpha MSH), ACTH, and other related peptides, was originally identified as a product of the pituitary gland. However, recent evidence shows that POMC products can also be produced by nonpituitary tissues. Because keratinocytes, the major constituent of the epidermis exhibit the capacity to release a variety of proinflammatory and immunomodulatory mediators, the present study was performed to investigate whether human keratinocytes are able to produce POMC-derived peptides. Supernatants of human normal keratinocytes and an epidermal carcinoma cell line (A431) contained significant levels of immunoreactive alpha MSH and ACTH. Upon immuneprecipitation and size-exclusion chromatography, keratinocyte-derived alpha MSH exhibited a molecular mass of approximately 1 kD and was biologically active as demonstrated in a tyrosinase bioassay. Northern blot analysis revealed the expression of POMC-specific transcripts (1.3 kb) in both normal keratinocytes and A431 cells. The production of alpha MSH and ACTH could be significantly upregulated both at the protein and mRNA level upon treatment with phorbol myristate acetate, ultraviolet light, or interleukin 1. These data provide first evidence that human keratinocytes produce POMC-derived peptides such as alpha MSH and ACTH. Because POMC-derived peptides recently have been recognized as potent immunomodulatory mediators, their presence in the epidermis may have a major impact on the skin immune system.
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PMID:Proopiomelanocortin-derived peptides are synthesized and released by human keratinocytes. 818 58

Silky Fowl is a natural mutant with hyperpigmentation of various internal tissues. Although the mechanism of hyperpigmentation remains unclear, recent studies have shown that the abnormal migration of melanoblast and the absence of environmental barrier molecules are responsible for the hyperpigmentation in Silky Fowl. In this study, 13 genes related to melanocyte development were selected to detect expression changes between Silky Fowl and White Leghorn [including SRY-box 10 (Sox10), paired box (Pax3), stem cell factor (Scf), v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (Kit), endothelin type-B receptor (Ednrb), endothelin 3 (Edn3), microphthalmia-associated transcription factor (Mitf), tyrosinase (Tyr), tyrosinase-related protein-1 (Trp1), tyrosinase-related protein-2 (Trp2), melanocortin-1 receptor (Mc1r), Agouti-related proteins (Agrp), and Proopiomelanocortin (Pomc)]. Transcript expression was detected in 11 stages from 2.5 to 15 days of incubation. In these embryonic periods, Mitf, Kit, Scf, and Agrp expressed earlier in Silky Fowl than in White Leghorn. Sox10, Ednrb, Kit, Mc1r, and Agrp, associating with the proliferation and differentiation of melanoblast, expressed higher (P < 0.05) in Silky Fowl than White Leghorn during 5-6 days of incubation. After day 8 of incubation, Mitf, Tyr, Trp1, Trp2, and Mc1r expressed higher (P < 0.05) in Silky Fowl than White Leghorn, while Agrp expressed higher (P < 0.05) in White Leghorn than Silky Fowl. Moreover, a regulatory network for melanocyte development was constructed based on the expression data. The network predicted novel regulatory relationships and confirmed relationships that have been reported. These results provide biological insight into the molecular mechanism of hyperpigmentation in the Silky Fowl. However, further investigation is needed to confirm these regulatory relationships.
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PMID:Expression and network analysis of genes related to melanocyte development in the Silky Fowl and White Leghorn embryos. 2084 20