ΔNp63 participates in the development and organization of Xenopus mucociliary epithelium

CELESTE TRÍBULO; MARÍA GUADALUPE BARRIONUEVO; EZEQUIEL CARRIZO; MANUEL AYBAR

Santos, Sao Paulo, Brasil

Congreso; VIII Meeting of Latin American Society for Developmental Biology; 2015

Latin American Society for Developmental Biology

It has been established in several models that thetranscription factor deltaNp63 has animportant role in the development of the epidermis and its derivatives. Our previous results demonstrated that deltaNp63 is regulated by BMP4 signalingpathway and participates in the early epidermis specification. The larvalepidermis of Xenopus laevis is abilayered epithelium which can be used as a model system for the study of thedevelopment and function of mucociliary epithelia. This tissue presents fourdifferent cellular types: Globet cells (GCs), ciliated cells (CCs), ionocytes(INCs) and small secretory cells (SSCs). GCs develop in the outer layer while CCs,INCs and SSCs sequentially intercalate from the inner to the outer layer. GCs arethe most abundant and highest with a polygonal shape. CCs are placed insolitary and they are characterized by the presence of multiple apical ciliawhile INCs are generally situated in pairs and their surface presentmicrovilli. Finally, SSCs have a triangular shape and big apical vesicles. Weanalyzed the participation of deltaNp63during the specification of these cellular types. After loss of function experiments,we performed an ultraestructural analysis of Xenopus embryonic epidermis by scanning electron microscopy (SEM). Twodifferent approaches were used to interfere with deltaNp63 function by means of different mechanisms. One of themconsisted in the microinjection of an antisense morpholino oligonucleotide (deltaNp63MO) and the other in theoverexpression of a C-terminally truncated form of deltaNp63 fused to a green fluorescent protein (deltaNp63(Ct)-GFP) which acts as adominant negative. The inhibition of deltaNp63leaded to alterations in the number, distribution and structure of epidermalcells. The number of CCs and INCs was augmented while SSCs number wasdiminished. Besides, INCs and GCs increased their size. CCs and INCs showed anabnormal spatial distribution, CCs were observed adjacent and INCs weredisposed in groups. Further, GCs and CCs presented an altered morphology. GCs losttheir polygonal shape while the alteration of CCs was characterized by thepresence of few and short cilia. These results suggest that deltaNp63 is involved in the correctformation of mucociliary epithelia in Xenopusembryos.