Feather follicles express two classes of pro-opiomelanocortin (POMC) mRNA using alternative promoters in chickens

Chihiro Yoshihara, Yuichi Tashiro, Shusuke Taniuchi, Harumi Katayama, Sumio Takahashi, Sakae Takeuchi

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Feather coloration in chickens mainly depends on melanin produced by melanocytes located in the feather follicles. The melanocortin 1 receptor (MC1R) on follicular melanocytes regulates melanin synthesis; however, the source of the melanocortins that interact with the receptors remains unclear. In this study, we examine the potential expression of melanocortins and characterize the mRNAs for the precursor pro-opiomelanocortin (POMC) in chicken feather follicles. Reverse transcription-polymerase chain reaction (RT-PCR) revealed the expression of mRNAs for POMC, prohormone convertase 1 (PC1) and PC2, and western blotting detected adrenocorticotropic hormone (ACTH)-related products of POMC processing in feather follicles, suggesting that melanocortins are produced locally in the tissues of chickens. A combination of 5′RACE (rapid amplification of cDNA 5′ end), 3′RACE and RT-PCR analyzes identified two classes of POMC mRNA, class a and class b, which encode the same full-length POMC protein but have different non-coding leader exons. Class a mRNAs were expressed specifically in feather follicles, whereas class b mRNAs were expressed in the pituitary, hypothalamus, and various peripheral tissues that we examined. Within the feather follicles, the class a mRNAs were distributed in epidermal layers from middle to distal locations, whereas the class b mRNAs were mainly expressed in pulp at proximal locations. Our findings suggest that feather pigmentation is regulated by locally produced melanocortins, and indicate that the melanocortins encoded by the different classes of POMC mRNAs may play different intra-follicular roles in chickens. This is the first report that demonstrates alternative promoter usage generating different full-length POMC mRNAs in vertebrates.

Original languageEnglish
Pages (from-to)46-51
Number of pages6
JournalGeneral and Comparative Endocrinology
Volume171
Issue number1
DOIs
Publication statusPublished - Mar 1 2011

Keywords

  • Alternative promoter
  • Chicken
  • Feather
  • MRNA isoform
  • POMC

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Endocrinology

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