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Delineating the role of MITF isoforms in pigmentation and tissue homeostasis

Jessica L Flesher1,2, Elyse K Paterson-Coleman3, Priya Vasudeva4

  • 1Department of Biological Chemistry, University of California, Irvine, CA, USA.

Pigment Cell & Melanoma Research
|September 29, 2019
PubMed

Insights

The microphthalmia-associated transcription factor (MITF) gene has distinct isoforms, MITF-A and MITF-M. MITF-M is crucial for melanocyte development and kidney size, while MITF-A plays a minor role in pigmentation.

Area of Science:

  • Genetics
  • Developmental Biology
  • Cell Biology

Background:

  • The microphthalmia-associated transcription factor (MITF) gene encodes multiple isoforms with unique amino termini, crucial for various cellular functions.
  • The precise roles of individual MITF isoforms in tissue-specific pigmentation and their regulatory mechanisms remain incompletely understood.

Purpose of the Study:

  • To elucidate the distinct functions of MITF-A and MITF-M isoforms in melanocytes and other tissues.
  • To identify regulatory elements controlling MITF isoform expression.

Main Methods:

  • Generation and analysis of Mitf-A and Mitf-M knockout mouse models.
  • Investigation of gene expression patterns, including Tyrosinase (Tyr).
  • Identification of a novel retinoid enhancer element regulating MITF-A expression.

Main Results:

  • Mitf-A knockout mice exhibited subtle changes in hair melanin and reduced Tyr expression in the eye.
  • Mitf-M-null mice displayed enlarged kidneys and a lack of neural crest-derived melanocytes in skin and choroid.
  • Despite Mitf-M deficiency, retinal pigment epithelium and iris pigment epithelium maintained pigmentation.

Conclusions:

  • MITF-M plays a critical role in melanocyte development and kidney size regulation.
  • MITF-A has a minor role in hair pigmentation and eye Tyr expression.
  • A novel retinoid enhancer element partially regulates MITF-A expression.
Keywords:
MITFCRISPR/CAS9alternative promoterschoroidisoformsmelanogenesismicrophthalmia-associated transcription factorretinal pigment epitheliumretinoids

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