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A novel NK-related mouse homeobox gene: expression in central and peripheral nervous structures during embryonic development.

We have identified three novel mouse homeobox genes that are related to the Drosophila NK gene family. Two genes without direct homologues in Drosophila were designated Nkx-5.1 and Nkx-5.2; the third gene Nkx-1.1 constitutes the mouse homologue to NK1.Nkx-5.1 and Nkx-5.2 are closely linked on mouse chromosome 7, whereas Nkx-1.1 is located on a different chromosome. Here, we report the spatiotemporal expression pattern of Nkx-5.1 during prenatal mouse development. Nkx-5.1 gene activity begins at Embryonic Day 10.5 in the developing ear, the neural tube, and dorsal root ganglia. It continues to be active throughout prenatal life in discrete regions of the brain with an anterior border in the ventral diencephalon at the optic chiasma and expression domains in mesencephalon, metencephalon, and myelencephalon. At midgestation, Nkx-5.1 is also expressed in mesenchyme of the head and branchial arches, and in some cranial ganglia, as well as in derivatives of neural crest, such as the truncus sympathicus and myenteric ganglia. The time pattern of Nkx-5.1 expression and its confinement to primarily postmitotic cells of the central and peripheral nervous system suggest that Nkx-5.1 may play a role in the specification of neuronal cell types.

Amino Acid Sequence↗

Expression of macrophage migration inhibitory factor in rat skin during embryonic development.

We have previously shown that human epidermal keratinocytes express macrophage migration inhibitory factor (MIF) mRNA, and immunohistochemical studies showed that MIF is expressed in human epidermis. To explore the possible pathophysiological roles of MIF in skin during rat fetal development, we examined the expression patterns of MIF during rat epidermal development using Northern blot analysis and in situ hybridization. Expression of MIF mRNA was first detected by in situ hybridization in the developing epidermis and hair germ cells from embryonic day (ED) 16. From ED 19, moderate levels of MIF expression were detected in the epidermis and epithelial sheath cells of growing hair follicles. In postnatal rat skin, higher MIF expression was detected in the epidermis and hair follicles on postnatal day 3. These observations were also confirmed by Northern blot analysis. Immunohistochemical analysis with an anti-MIF antibody showed a similar distribution to that of the mRNA. Our results suggest that MIF is associated with epidermal and hair follicle development.

Animals↗

Five specificity patterns of (1----3)-alpha-L-fucosyltransferase activity defined by use of synthetic oligosaccharide acceptors. Differential expression of the enzymes during human embryonic development and in adult tissues.

The use of synthetic trisaccharides as acceptors led to the definition of five main (1----3)-alpha-L-fucosyltransferase activity patterns in human adult tissues: (I). Myeliod cells, granulocytes, monocytes, and lymphoblasts, transfer an alpha-L-fucopyranosyl group to O-3 of a 2-acetamido-2-deoxy-D-glucosyl residue of H blood-group Type 2 oligosaccharide [alpha-L-Fucp-(1----2)-beta-D-Galp-(1----4)-beta-D-GlcpNAc----R] with Mn2+ as activator. (II) Brain has the same acceptor specificity pattern as myeloid cells, but can also use Co2+ as activator. (III) Plasma and liver transfer an alpha-L-furopyranosyl group to H blood-group Type 2 and to sialyl-N-acetyllactosamine [alpha-NeuAc-(2----3)-beta-D-Galp-(1----4)-beta-D-GlcpNAc----R]. (IV) Intestine, gall bladder, kidney, and milk have the same activity as (III), but also transfer an alpha-L-fucopyranosyl group to O-4 of a 2-acetamido-2-deoxy-D-glucose residue of H blood-group Type 1 [alpha-L-Fucp-(1----2)-beta-D-Galp-(1----3)-beta-D-GlcpNAc----R] and sialyl Type 1 [alpha-NeuAc-(1----3)-beta-D-Galp-(1----3)-beta-D-GlcpNAc----R]. (V) Stomach mucosa is not able to use sialyl-N-acetyllactosamine, but can transfer an alpha-L-fucopyranosyl group to the other Type 1 and Type 2 acceptors. Unlike in adult tissue, a single myeloid-like pattern of (1----3)-alpha-L-fucosyltransferase activity was found at early stages of development in all tissues tested. This embryonic enzyme is later progressively replaced by enzymes or mixtures of enzymes having the corresponding adult patterns of enzyme expression. All lymphoblastoid cell lines and half of the tumor epithelial cell lines tested expressed the myeloid-like pattern of enzyme found in normal embryonic tissues. The remaining tumor epithelial cell lines expressed different forms of (1----3/4)-alpha-L-fucosyltransferase acceptor specificity patterns.

Aging↗