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Parental imprinting of human H19 and IGFII genes
A.12
Placenta
(1992),
PARENTAL IMPRINTING OF HUMAN H19 AND IGFII GENES Nathan de Groot, Jacob Rachmelewitz, Ran Goshen, Ilana Ariel, Tamar Schneider and Abraham Ho&berg, Department of Biological Chemistry, Hebrew University, Jerusalem 91904, Israel. The H19 and IGF-II genes are highly expressed both in human extraembryonic and embryonic tissues. The highest expression of the two genes was observed in the fetal adrenal gland, and no expression was found in fetal brain cortex. Roth genes are repressed in adult tissues. The two genes are tightly linked on human chromosome '1 P 15.5. The H19 gene is maternally imprinted in mice and was found to IGF-II was be expressed in a mono-allelic manner in the human. proven to be paternally imprinted in mice. We were the first to use the androgenetic complete molar tissue to ascertain whether imprinted genes expressed in the placenta are maternally or paternally imprinted in the human. H19 and IGF-II are both expressed in human placenta, H19 is not expressed in the molar tissue, but IGF-II is expressed in this tissue. Our conclusion is that H19 is maternally and IGF-II is paternally imprinted in man.
ULTRASTRUCTURAL CHARACTERIZATION OF THE EXTRAVILLOUS TROPHOBLAST (EVT) CELLS DIFFERENTIATED IN VlTRO Karen deMesy Jensen, Olga Genbacev, P.A. di Sant Agnese and Richard K. Miller. Departments of ObslGyn and Pathology, Environmental Health Science Center, University of Rochester, Rochester, New York 14642 USA During implantation in humans, EVT cells invade the endometrium, myometrium and maternal uterine blood vessels. These cells differentiate by proliferation from the cell column of the anchoring villi of the first trimester placentae. The current knowledge of EVT cell morphology and role comes from the histological and histopathological studies of the early pregnancy hysterectomy specimens. Tissue explants of anchoring villi of first trimester placentae cultured on extracellular matrix give rise to EVT cells in vitro. This experimental model has been used to study ultrastructural characteristics of the EVT cells during differentiation and migration into the matrix. The whole cultures (tissue and matrix) were embedded in Spurr epoxy resin and semi-thin sections were used to “pop-off” the selected areas for electron microscopical examination. EVT cells recovered in the matrix outside the villous tissue after 48 hours in culture appeared in groups of 4-6 cells or as large, individual, round cells. Their cytoplasm contained abundant elongated, branched cistemae of granular endoplasmic reticulum, numerous mitochondria, lipid droplets and large pools of glycogen granules. Microvilli were present on the free surface of the cell membranes or covered the whole surface of the individual cells. These ultrastructural characteristics of the in vitro differentiated EVT cells are the same as the interstitial EVT cells from the basal plate of early pregnancy hysterectomy specimens. Therefore, the described in vitro system can be used for further study of EVT cell differentiation and regulation. (Supported by grant NIH ES02774 and Al32319.)
Voi 13
Placenta
(1992),
PARENTAL IMPRINTING OF HUMAN H19 AND IGFII GENES Nathan de Groot, Jacob Rachmelewitz, Ran Goshen, Ilana Ariel, Tamar Schneider and Abraham Ho&berg, Department of Biological Chemistry, Hebrew University, Jerusalem 91904, Israel. The H19 and IGF-II genes are highly expressed both in human extraembryonic and embryonic tissues. The highest expression of the two genes was observed in the fetal adrenal gland, and no expression was found in fetal brain cortex. Roth genes are repressed in adult tissues. The two genes are tightly linked on human chromosome '1 P 15.5. The H19 gene is maternally imprinted in mice and was found to IGF-II was be expressed in a mono-allelic manner in the human. proven to be paternally imprinted in mice. We were the first to use the androgenetic complete molar tissue to ascertain whether imprinted genes expressed in the placenta are maternally or paternally imprinted in the human. H19 and IGF-II are both expressed in human placenta, H19 is not expressed in the molar tissue, but IGF-II is expressed in this tissue. Our conclusion is that H19 is maternally and IGF-II is paternally imprinted in man.
ULTRASTRUCTURAL CHARACTERIZATION OF THE EXTRAVILLOUS TROPHOBLAST (EVT) CELLS DIFFERENTIATED IN VlTRO Karen deMesy Jensen, Olga Genbacev, P.A. di Sant Agnese and Richard K. Miller. Departments of ObslGyn and Pathology, Environmental Health Science Center, University of Rochester, Rochester, New York 14642 USA During implantation in humans, EVT cells invade the endometrium, myometrium and maternal uterine blood vessels. These cells differentiate by proliferation from the cell column of the anchoring villi of the first trimester placentae. The current knowledge of EVT cell morphology and role comes from the histological and histopathological studies of the early pregnancy hysterectomy specimens. Tissue explants of anchoring villi of first trimester placentae cultured on extracellular matrix give rise to EVT cells in vitro. This experimental model has been used to study ultrastructural characteristics of the EVT cells during differentiation and migration into the matrix. The whole cultures (tissue and matrix) were embedded in Spurr epoxy resin and semi-thin sections were used to “pop-off” the selected areas for electron microscopical examination. EVT cells recovered in the matrix outside the villous tissue after 48 hours in culture appeared in groups of 4-6 cells or as large, individual, round cells. Their cytoplasm contained abundant elongated, branched cistemae of granular endoplasmic reticulum, numerous mitochondria, lipid droplets and large pools of glycogen granules. Microvilli were present on the free surface of the cell membranes or covered the whole surface of the individual cells. These ultrastructural characteristics of the in vitro differentiated EVT cells are the same as the interstitial EVT cells from the basal plate of early pregnancy hysterectomy specimens. Therefore, the described in vitro system can be used for further study of EVT cell differentiation and regulation. (Supported by grant NIH ES02774 and Al32319.)
Voi 13