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Caterina Missero, Ph.D. Group
Leader,
Centre of Genetics Engineering E-mail: missero@ceinge.unina.it Ph.D. in Biology, University of Trieste (Trieste, Italy), 1989 |
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Molecular
basis of skin development and disease. Our
research focuses on studying the transcriptional mechanisms and genetic
pathways required for normal skin development, and on the identification of
genetic alterations that occur in inherited and in acquired skin diseases.
Stratified epithelia of the skin, such as the epidermis and the hair
follicle, are constantly self-renewing tissues that provide a fascinating
system with which to study the molecular and cellular mechanisms governing
tissue formation and homeostasis. Using primary keratinocytes
derived from human and mouse skin, as well as mouse genetic models, we are
investigating how epithelial cells in the skin initiate stratification and
regulate their differentiation to establish unique programs of gene
expression. To
tackle this problem we are using functional genomics and molecular biology
approaches starting from the identification of upstream regulators and
downstream effectors of the transcription factor p63, a crucial regulator of
stratified epithelia. Pathways
downstream of p63 We recently identified a
number of p63 target genes using genome-wide expression profiling, and by chromatin immunoprecipitation on a
chip (ChIP-chip) to identify p63-bound regions in vivo (Della Gatta
et al., 2008). To identify immediate early-responsive genes,
we engineered a tamoxifen-responsive p63 protein
(ERp63). We found that a large number of genes were directly regulated by
p63. p63 induced several genes involved in cell
cycle progression, thus positively controlling proliferation. In contrast,
p63 also directly suppressed a subset of genes encoding for late
differentiation markers, while it affected others indirectly. Among the signaling
pathways involved in embryonic development, we demonstrated that p63 plays a
key role in regulating keratinocyte differentiation
at least in part through cross-regulation with Notch1. In keratinocytes,
Notch1 is required to
restrict growth and promote differentiation, whereas p63 has the opposite
function. p63 negatively modulates Notch1 function by
directly suppressing the expression of the Notch1 downstream effector Hes-1
(Nguyen et al., 2006). Conversely, p63 expression is suppressed by Notch1 activation through a mechanism
requiring down-modulation of selected interferon-responsive genes. Thus, a
complex cross-talk between Notch and p63 is involved in the balance between keratinocyte self-renewal and differentiation. In addition, we find a
previously uncovered role of p63 in controlling Bone Morphogenetic Protein
(BMP) signaling, which is required for maintaining low expression levels of several non-epidermal genes. p63 represses
transcription of the inhibitory Smad7 and activates Bmp7, thereby sustaining BMP signaling. In the absence of
p63, compromised BMP signaling leads to inappropriate non-epidermal
gene expression in postnatal mouse keratinocytes
and in embryonic epidermis. Reactivation of BMP signaling by Smad7 knockdown
and/or –to a lesser extent– by BMP treatment suppresses
expression of non-epidermal genes in the absence of p63. Canonical BMP/Smad signaling is essential for control of non-epidermal
genes as use of a specific inhibitor, or simultaneous knockdown of Smad1 and
Smad5 counteract suppression of non-epidermal genes. Mechanisms
underlying the ectodermal defects in a human
genetic disorder caused by heterozygous mutations in p63 Ankyloblepharon-ectodermal defect-cleft
lip and/or palate (AEC or Hay-Well syndrome) is a rare autosomic
dominant disorder caused by missense mutations in
the p63 coding sequence. AEC results in severe skin erosion at birth, as well
as ectodermal dysplasia, ankyloblepharon (fusion of the eyelid margins), and cleft
palate with or without cleft lip. Although p63 null mice have contributed significantly to elucidation of
the function of p63 in the epidermis, little is known about the pathogenesis
of AEC syndrome. To dissect the molecular defects underlying AEC syndrome, we
generated a unique knock-in mouse model (p63+/L514F)
that carries a clinically relevant point mutation in the SAM
(sterile-alpha-motif) domain of the p63
alpha isoform. Characterization of this mouse
model will be instrumental to understand the pathogenesis of the AEC
syndrome. Tissue-specific
regulation of p63 expression p63 is one of the
earliest markers of stratified epithelia during development, however the
mechanisms controlling p63 expression are still poorly understood. Using a
genomic sequence comparison approach across multiple vertebrate species, we
isolated a highly conserved distal enhancer in the p63 locus that confers
strong tissue-specific activity in transgenic mice (Antonini
et al., 2006). Functional characterization of the enhancer has revealed an autoregulatory feedback loop in which the p63 protein
directly binds and is an essential regulator of the enhancer. We are
currently searching for other genomic elements in the p63 locus that
contribute to regulate p63 gene expression. These studies will be crucial to
identify major determinants of gene expression in stratified epithelia. Bibliography Brancaccio,
A., Minichiello, A., Grachtchouk, M., Antonini, D., Sheng, H., Parlato, R.,
Dathan, N., Andrzej A. Dlugosz, Missero, C. (2004). Requirement of the forkhead
gene Foxe1, a target of sonic
hedgehog signaling, in hair follicle morphogenesis. Hum. Mol. Gen., 13 (21): 2595-2606. Wang,
J., Devgan, V., Corrado, M., Missero,
C., Dotto, G.P. (2005). GITR is a p21WAF1/Cip1 transcriptional
target conferring resistance of keratinocytes to
UV-induced apoptosis. J. Biol. Chem.,
280 (45): 37725-31. Antonini,
D., Rossi, B., Han, R., Minichiello, A., Di Palma, T., Corrado, M., Banfi,
S., Zannini, M., Brissette, J.L., Missero,
C. (2006). An evolutionarily conserved long-range enhancer controls p63
expression through a positive autoregulatory loop.
Mol. Cell. Biol., 2006;26 3308-3318. Nguyen, B-C., Lefort, K., Mandinova, A., Antonini, D., Devgan, V., Della
Gatta, G., Koster, M.I.,
Zhang, Z., Wang, J., Tommasi di
Vignano, A., Kitajewski,
J., Chiorino, G., Roop,
D.R., Missero*, C. Dotto*,
G.P., (2006). Cross-regulation between Notch and p63 in keratinocyte
commitment to differentiation. Genes Dev.,
2006; 20 1028-1042. (*equal contribution). Dentice M, Luongo C, Huang S, Ambrosio R, Elefante A, Mirebeau-Prunier D,
Zavacki AM, Fenzi G, Grachtchouk M, Hutchin M, Dlugosz AA, Bianco AC, Missero C, Larsen PR, Salvatore D. (2007). Sonic
hedgehog-induced type 3 deiodinase blocks thyroid
hormone action enhancing proliferation of normal and malignant keratinocytes. Proc Natl Acad Sci U S A,104(36):14466-71. Roure A, Rothbacher U, Robin F, Kalmar
E, Ferone G, Lamy C, Missero C, Mueller F, Lemaire
P. (2007). A multicassette gateway vector set for
high throughput and comparative analyses in ciona
and vertebrate embryos. PLoS ONE,
2(9):e916. Antonini,
D., Dentice, M., Mahtani, P., De Rosa, L., Della Gatta, G., Mandinova, A.,
Salvatore, D., Stupka, E., Missero, C. (2008). Tprg, a gene
predominantly expressed in skin, is a direct target of the transcription factor
p63. J Invest Dermat, 128(7):
1676-1685. Della
Gatta, G., Bansal, M., Ambesi-Impiombato, A.,
Antonini, D., Missero*, C., di Bernardo*, D. (2008). Direct targets
of the Trp63 transcription factor revealed by a combination of gene
expression profiling and reverse engineering. Genome Research, 18(6): 939-48.
(*co-corresponding author and equal contribution). Fete M, vanBokhoven H,
Clements SE, McKeon F, Roop DR, Koster
MI, Missero C, Attardi
LD, Lombillo VA, Ratovitski
E, Julapalli M, Ruths D, Sybert VP, Siegfried EC, Bree
AF. (2009). International Research Symposium on Ankyloblepharon-Ectodermal
Defects-Cleft Lip/Palate (AEC) syndrome. The American Journal of Medical
Genetics, 149A(9):1885-93. De Rosa L*, Antonini D*, Ferone G, Russo MT, Yu PB, Han R,
Missero C. (2009). p63 Suppresses non-epidermal
lineage markers in a bone morphogenetic protein-dependent manner via
repression of Smad7. The Journal of Biological Chemistry, 284(44):30574-82. (*equal
contribution). |
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