Project description:<p>In order to create a melanocyte-specific eQTL resource, we obtained primary human melanocyte cultures isolated from foreskin of 106 healthy newborn males predominantly of European descent. Melanocytes were cultured in lot-matched culture medium in randomized batches to minimize variability that could be introduced by culturing conditions. RNA sequencing and direct SNP genotyping of these samples produced an average of ~87.9 million reads (paired-end, stranded, 126bps), and ~713,000 SNP genotypes, respectively.</p>
Project description:Little is known about the mechanisms underlying the localization of human melanocytes during embryogenesis, and how the characteristics of melanocytes differ in various body sites. Immunohistochemical studies of biopsy tissue obtained from four different anatomic sites (scalp, back, abdomen, and sole) of 31 aborted fetuses following the approval of the ethics committee for the study of human gene analysis revealed that the melanocyte-associated marker gp100 was expressed earlier in embryogenesis than other melanocyte markers. Human fetal melanocytes are initially localized in the epidermis, and then migrate to the hair buds from the epidermis but not the dermis. In the sole, melanocytes localize in eccrine sweat gland ducts. Cultured fetal melanocytes did not stain positively for any melanocyte markers other than MITF and nestin. When co-cultured with normal human keratinocytes and fibroblasts, fetal melanocytes stained positively for gp100. Gene expression studies indicated that fetal melanocytes were topographically diverse, especially sole-derived melanocytes compared with other melanocytes. Expression of several genes, including CHI3L1 and FGF7, was higher in sole-derived melanocytes. These findings suggest that human fetal melanocytes derived from the sole have different profiles both in vivo and in vitro compared with melanocytes from other sites.
Project description:Little is known about the mechanisms underlying the localization of human melanocytes during embryogenesis, and how the characteristics of melanocytes differ in various body sites. Immunohistochemical studies of biopsy tissue obtained from four different anatomic sites (scalp, back, abdomen, and sole) of 31 aborted fetuses following the approval of the ethics committee for the study of human gene analysis revealed that the melanocyte-associated marker gp100 was expressed earlier in embryogenesis than other melanocyte markers. Human fetal melanocytes are initially localized in the epidermis, and then migrate to the hair buds from the epidermis but not the dermis. In the sole, melanocytes localize in eccrine sweat gland ducts. Cultured fetal melanocytes did not stain positively for any melanocyte markers other than MITF and nestin. When co-cultured with normal human keratinocytes and fibroblasts, fetal melanocytes stained positively for gp100. Gene expression studies indicated that fetal melanocytes were topographically diverse, especially sole-derived melanocytes compared with other melanocytes. Expression of several genes, including CHI3L1 and FGF7, was higher in sole-derived melanocytes. These findings suggest that human fetal melanocytes derived from the sole have different profiles both in vivo and in vitro compared with melanocytes from other sites. In this study, microarray analyses were performed using cultured fetal melanocytes from 4 different sites (scalp, back, abdomen and sole) obtained at 19 WOG, and newborn normal epidermal melanocyte as a control. RNA purification was performed using an RNeasy Mini kit (Qiagen, Germany) and those 5 samples, were analyzed using GeneChip 1.0 ST Array (Affymetrix, CA, USA).
Project description:Target genes of ultraviolet stress response in cutaneous melanocytes, potentially associated with solar induced melanocarcinogenesis, were characterized by cDNA microarray technology. In cultured normal human melanocytes, 198 genes out of »9000 arrayed were found modulated > 1.9 times following artificial ultraviolet (mainly ultraviolet-B) irradiation (100 mJ per cm2).
Project description:To identify microRNAs potentially involved in melanomagenesis we compared microRNA transcription profiles between melanoma cell lines and cultured melanocytes.
Project description:DICER is a central regulator of microRNA maturation. However little is known about mechanisms regulating its expression in development or disease. While profiling miRNA expression in differentiating melanocytes, two populations were observed: some upregulated at the pre-miRNA stage, and others upregulated as “mature” miRNAs (with stable pre-miRNA levels). Conversion of pre-miRNAs to fully processed miRNAs appeared to be dependent upon stimulation of DICER expression—an event found to occur via direct transcriptional targeting of DICER by the melanocyte master transcriptional regulator MITF. MITF binds and activates a conserved regulatory element upstream of DICER’s transcriptional start site upon melanocyte differentiation. Targeted knockout of DICER is lethal to melanocytes, at least partly via DICER-dependent processing of the pre-miRNA-17~92 cluster thus targeting BIM, a known pro-apoptotic regulator of melanocyte survival. These observations highlight a central mechanism underlying miRNA regulation which could exist for other cell types during development. Primary melanocytes were obtained from 7 independent donors. Mature-miRNA levels were detected using Applied Biosystem's TaqMan PCR assay.