Ectoderm

Robert, B., Lyons, G., Simandle, B. K., Kuroiwa, A., and Buckingham, M. (1991). The apical ectodermal ridge regulates Hox-7 and Hox-8 gene expression in developing chick limb buds. Genes Dev. 5 2363-2374. 

Mayer, T. C., and Fishbane, J. L. (1972). Mesoderm-ectoderm interaction in the production of the agouti pigmentation pattern in mice. Genetics 71 297-303. 

Schweitzer R, Shaharabany M, Seger R, Shilo BZ 1995 Secreted Spitz triggers the DER signaling pathway and is a limiting component in embryonic ventral ectoderm determination. Genes Dev 9 1518-1529... 

The FGFs stimulate the proliferation of mesodermally and ectodermally-derived cells and play central roles in mammalian development. Members of the FGF family are expressed in the embryonic period and are required for several critical events in neural development and specifically for neural induction. FGF-8 is necessary for positional identity required for axial specification and patterning of limb development. FGF-2 stimulates the proliferation of multipotential stem cells that subsequently give rise to neurons of the cortex and other brain regions. 

Liem, K. J., Tremmel, G., Roelink, H. and Jessel, T. Dorsal differentiation of neural plate cells induced by BMP-mediated signals from epidermal ectoderm. Cell 82 969-979, 1995. 

Animal tissues usually contain low levels (<0.3 mg As/kg fresh weight) of arsenic. After the administration of arsenicals, these levels are elevated, especially in liver, kidney, spleen, and lung and several weeks later, arsenic is translocated to ectodermal tissues (hair, nails) because of the high concentration of sulfur-containing proteins in these tissues. 

The functions of vitamin A in the maintenance of epithelial cell integrity (Wolbach and Howe, 1925) emerged more slowly. An experiment by Fell and Mellanby (1953) with embryonic chick ectoderm cultures showed that in the presence of very high, non-physiological... 

Fell, H.B. Mellanby, E. (1953). Metaplasia produced in cultures of chick ectoderm in high vitamin A. J. Physiol. 119,470-488. 

Ryan KR, Lawson CA, Lorenzi AR, Arkwright PD, Isaacs JD, Lihc D CD4+CD25+ T-regulatory cells are decreased in patients with autoimmune polyendocrinopathy candidiasis ectodermal dystrophy. J Allergy Clin Immunol 2005 116 1158-1159. 

Fig. 1. Hydra oligactis whole mount labeled with monoclonal antibody JDl. (A) Isolated ganglionic neuron in the body column, scale bar = 50 om (B) hypostomal nerve net with sensory neurons of the mouth at the left and ganglionic neurons of the perihypostomal ring to the right, scale bar = 50 pm (C) cell bodies of hypostomal sensory neurons extending from the mesoglea (processes) to the surface of the ectoderm, scale bar = 25 pm.

Trafe TNF-receptor-associated factor 6 Osteopetrosis with reduced osteoclasts Deficiency of l3miph nodes, Hipohidrotic ectodermal dysplasia... 

Naito, A., Yoshida, H., Nishioka, E., Satoh, M., Azuma, S., Yamamoto, T., Nishikawa, S L, and Inoue, J-1. (2002) TRAE6 Deficient Mice Display H3rpohidrotic Ectodermal Dysplasia. 

Smashi, A., Courtois, G., Rabia, S.H., Doffinger, R., Bodemer, C., Munnich, A., Casanova, J.L., and Israel, A. (2002) The NF-kappaB Signaling Pathway in Human Diseases from Incontinentia Pigmenti to Ectodermal Dysplasias and Immime Deficiency Syndromes. 

The ESC of hamsters, rabbits, sheep, pigs, cattle, and primates are obtained from three embryonic layers, these are ectoderm, endoderm and mesoderm. The lines of murine permanent ESC are known. J. A. Thompson et al. (1996-1998) obtained several lines of permanent ESC of human from internal cellular mass (ICM) of blastocyst. 

According to the accepted definition SC, resulting in only one type of the differentiated cells, are named unipotential (or monopotential), two - bipotential. Those cells which give the beginning to a few types of different specialized cells are named pluripotential or multipotential. Totipotential is the ability of cell to differentiate in all the types of cells and tissues of organism (in any of 350 specialized lines derivative of ectoderm, mesoderm and endoderm). 

In Xenopus, in addition to the role in 5S RNA gene regulation, somatic HI has been shown to be involved in further stages of differentiation. The restriction of myoD expression, a marker for the loss of the ability by ectodermal cells to differentiate into mesoderm, requires the presence of somatic histone HI [144]. Again, the globular domain alone and not the whole HI molecule is required to confer this effect [142]. 

Stem cells are present in the earliest stage of embryonic development the blastocyst. Embryonic stem cells are pluripotent, meaning they are capable of generating any terminally differentiated cell in the human body that is derived from any one of the three embryonic germ layers ectoderm, mesoderm, or endoderm [8]. All the body s organs arise through a series of divisions and differentiations from the original embryonic stem cells that form the blastocyst [3]. 

Cord blood has long been used as a source of MSCs for bone marrow transplantation. The stem cell compartment is more abundant and less mature in cord blood than in bone marrow. Moreover, MSCs in cord blood have a higher proliferative potential because of their extended lifespan and longer telomeres [91-94]. Not only can cord-blood MSCs be harvested without morbidity to the donor, but they also display a robust in vitro capacity for directable or spontaneous differentiation into mesodermal, endodermal, and ectodermal cell fates. Cord-blood MSCs are CD45 and HLA-II and can be expanded without losing their pluripotency. Therefore, cord blood is also undergoing preclinical evaluation as a possible easily accessible source of multipotent cells. 

Figure 8.3 Specialized cells and tissues in our body develop in stages. The embryo inner cell mass develops into three layers the outer layer, or ectoderm, that will become skin, eyes, and nerves the inner cell layer, the endoderm, that develops into the lungs, liver, and the lining of our digestive system and the middle layer, the mesoderm, that develops into bones, muscle, and blood.

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