Expression of paired-like homeodomain transcription factor 2c (PITX2c) in epidermal keratinocytes.
Paired-like homeodomain transcription factor 2 (PITX2) has been implicated as one of the genes responsible for Rieger syndrome. It has been also shown to play a central role during development. In this study, we investigated the functional role of PITX2 in keratinocyte differentiation. RT-PCR analysis showed that PITX2c isoform was predominantly expressed in a differentiation-dependent manner. Consistent with, immunohistochemical staining showed that PITX2 expression was increased in the upper layer of epidermis. When PITX2c was overexpressed in cultured keratinocytes by a recombinant adenovirus, the differentiation markers such as involucrin and loricrin were significantly increased at both mRNA and protein levels. In addition, PITX2c overexpression led to the decrease of cell growth, concomitantly with the upregulation of cell cycle-related genes p21. To investigate the effect of PITX2c in vivo, we microinjected PITX2c expression vector into zebrafish embryo. Interestingly, overexpression of PITX2c in zebrafish embryo led to the formation of horn-like structure and thickening of epidermis, together with the increase of keratin 8 (K8) expression. These results suggest that PITX2c has a role in proliferation and differentiation of epidermal keratinocytes.
Shi
Ge
G
Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, 301-747, Republic of Korea.
Sohn
Kyung-Cheol
KC
Choi
Tae-Young
TY
Choi
Dae-Kyoung
DK
Lee
Sang-Sin
SS
Ou
Bai-sheng
BS
Kim
Sooil
S
Lee
Young Ho
YH
Yoon
Tae-Jin
TJ
Kim
Seong-Jin
SJ
Lee
Young
Y
Seo
Young-Joon
YJ
Lee
Jeung-Hoon
JH
Kim
Chang Deok
CD
D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D000078404:Epidermal Cells; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D015027:Zebrafish / Q000196:embryology; D000097577:Homeobox Protein PITX2
D018398:Homeodomain Proteins; D014157:Transcription Factors; D000097577:Homeobox Protein PITX2