Molecular cloning of cDNA encoding a novel microphthalmia-associated transcription factor isoform with a distinct amino terminus.
Microphthalmia-associated transcription factor mutations are associated with white-spotted coat color in swamp buffalo.
MicroRNA-340-mediated degradation of microphthalmia-associated transcription factor
mRNA is inhibited by the coding region determinant-binding protein.
Furthermore, a-melanocyte-stimulating hormone (a-MSH) and cAMP-elevating agents, such as forskolin and IBMX, through the activation of protein kinase A (PKA) and cAMP-related element binding protein (CREB) transcription factor, promote an increase in the expression of microphthalmia-associated transcription factor
(MITF), a master regulator of the development and differentiation of melanocytes.
Abbreviations: CDK4, cyclindependent kinase 4; CK, cytokeratin; HMB-45, human melanoma black 45; Mart-1, melanoma-associated antigen recognized by Tcells 1; MDM2, mouse double minute 2 homolog; MiTF, microphthalmia-associated transcription factor
; MPNST, malignant peripheral nerve sheath tumor; SOX10, sex-determining region Y box 10; TLE1, transducin-like enhancer of split 1.
Microphthalmia-associated transcription factor
as a regulator for melanocyte-specific transcription of the human tyrosinase gene.
The mRNA expression of tyrosinase and tyrosinase-related proteins-1 and -2 was also hindered by 7-(4(")-hydroxy3(")-methoxyphenyl)-l-phenylhept-4-en-3-one, kaempferide, and galangin, as was the protein level of a microphthalmia-associated transcription factor
, the authors noted (Bioorg.
To establish the identity of the tumor and further characterize the tumor cells, staining with a broad panel of immunohistochemical stains (pankeratin, synaptophysin, chromogranin, CD56, neuron-specific enolase, smooth muscle actin, desmin, CD117 [c-KlT], CD34, S100, human melanoma black-45 [HMB-45], melanocyte differentiation antigen [Melan-A], microphthalmia-associated transcription factor
[MiTF], TFE3, neurofilament protein, glial fibrillary acidic protein, estrogen receptor, and progesterone receptor) and electron microscopy were performed.
Given the history of metastatic melanoma to ipsilateral regional nodes 20 years previously, and because neither slides nor microscopic description of the previous tumor were available for review, immunohistochemical stains for melanocyte differentiation markers were performed, including S100, Melan-A, HMB-45, PNL-2, and microphthalmia-associated transcription factor
. CD117 staining was also performed, and CD117 was the only marker significantly positive within an initial panel (Figure 3, A).
It is important to recognize that many alterations in genetic and cell-signaling pathways have been implicated in melanoma, with the following suggested as susceptibility gene(s): CDKN2A (cyclin-dependent kinase inhibitor 2A); CDK4 (cyclin-dependent kinase 4); MC1R (melanocortin 1 receptor); MITF (microphthalmia-associated transcription factor
); BCL2; PTEN (phosphatase and tensin homolog); CDKN2A ([p14.sup.ARF] gene product); TP53 (tumor protein p53); AKT;c-KIT; and RAS and BRAF (involved in mitogen activated protein kinase pathway).
Immunohistochemical and reverse transcription-polymerase chain reaction expression analysis of tyrosinase and microphthalmia-associated transcription factor
The transcription factor binding to IGHM enhancer 3 (TFE3) protein belongs to a family of basic helix-loop-helix/leucine zipper transcription factors that also includes transcription factor EB (TFEB), transcription factor EC, and microphthalmia-associated transcription factor
. (65-74) These proteins may homodimerize or heterodimerize to bind DNA.