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J Oberdick

Publications and source records attributed to J Oberdick.

30 records · Page 2Linked to original sources
PubMed1993

Control of segment-like patterns of gene expression in the mouse cerebellum.

A Purkinje cell-specific transgene, L7-lacZ, is expressed in a series of parasagitally oriented stripes in the mouse cerebellum. This banding pattern can be perturbed by promoter mutation, showing that a combination of positive and negative control elements contributes to the temporal and spatial map of L7 gene expression. In addition to the parasagittal stripes, certain mutations reveal Purkinje cells organized into compartments oriented in the transverse plane of the cerebellum. Transcription factors of the POU or homeobox families appear to be involved in controlling L7 expression in the transverse orientation. Strikingly, some of the domains of gene expression revealed by the mutations appear to correspond to functional compartments of Purkinje cells, thereby suggesting an underlying genetic principle used to orchestrate functional organization in the nervous system.

Animals↗
PubMed1993

A fos-lac Z transgenic mouse that can be used for neuroanatomic mapping.

Cellular immediate-early genes are rapidly induced by a diverse range of agents and conditions. Since many cIE genes encode known or potential transcription factors, they are believed to couple extracellular stimuli to long-lasting alterations in cellular phenotype through the regulation of gene transcription. In addition, the localization of the products of cIE genes has been used as a method for determining the cellular sites of action of particular agents in the nervous system. However, the methods of analysis are tedious, and the results may be ambiguous because of cross-reaction of reagents with related proteins. To further the utility of this approach, a bacterial gene encoding beta-galactosidase (lac Z) has been fused, in frame, into the fourth exon of c-fos, and this fos-lac Z fusion gene has been introduced into the germ line of mice. We have analyzed the expression of beta-galactosidase (under the control of the c-fos promoter) in the developing and adult nervous systems of these transgenic mice. As far as can be determined, the constitutive and stimulated expression of the transgene accurately reflects the expression of cognate c-fos in both cultured cells and the intact animal. This study has also revealed novel sites of constitutive and induced expression of c-fos that were overlooked using conventional analysis. In particular, constitutive expression of c-fos is associated with cells that are entering terminal differentiation and are destined to die. In addition, induced expression of the transgene in adult brain mirrors the pattern of neurotoxicity elicited by kainic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

fos-lacZ transgenic mice: mapping sites of gene induction in the central nervous system.

A transgenic mouse line containing a fos-lacZ fusion gene was derived in which beta-galactosidase activity identified cell populations expressing fos either constitutively or after stimulation. Seizures and light pulses induced nuclear lacZ activity in defined populations of neurons in vivo, and an array of neurotransmitters, including glutamate, induced the transgene in primary brain cultures. In unstimulated mice, the major sites of fos-lacZ expression were skin, hair follicle, and bone. fos-lacZ mice provide a new avenue for activity mapping studies based on gene expression.

Adrenal Glands↗
PubMed1991

Dynamic organization of developing Purkinje cells revealed by transgene expression.

The cerebellum has many properties that make it a useful model for investigating neural development. Purkinje cells, the major output neurons of the cerebellar cortex, have drawn special attention because of the availability of biochemical markers and mutants that affect their development. The spatial expression of L7, a protein specific for Purkinje cells, and L7 beta Gal, a gene expressed in transgenic mice that was constructed from the L7 promoter and the marker beta-galactosidase, delineated bands of Purkinje cells that increased in number during early postnatal development. Expression of the transgene in adult reeler mutant mice, which show inverted cortical lamination, and in primary culture showed that the initial expression of L7 is intrinsic to Purkinje cells and does not depend on extracellular signals. This may reflect an underlying developmental map in cerebellum.

Aging↗
PubMed1991

Cerebellar Purkinje cell markers are expressed in retinal bipolar neurons.

Previous studies have been directed at the elucidation of neuron-specific gene expression in the mammalian central nervous system. In particular, we have identified a series of marker molecules that are expressed in cerebellar Purkinje cells with varying degrees of specificity. Here, we show by light microscopic immunocytochemistry and Northern transfer and hybridization that two of these markers, namely, L7 and PEP19, are expressed in the retina of mouse and rabbit, while a third marker, cerebellin, is absent. Light and electron microscopic immunocytochemistry proves that L7-like immunoreactivity is restricted to rod bipolar cells, while PEP 19-like immunoreactivity is distributed in both rod and cone bipolars. PEP19 is also expressed by subsets of amacrine and ganglion cells. The density of PEP19-positive bipolar cells is greater than that of L7-positive bipolar cells, although the density of each is approximately equal in central and peripheral portions of the retina. An antiserum to a fourth Purkinje cell marker, vitamin D-dependent calcium-binding protein-28 kD (CaBP), reveals primarily axonless horizontal cells, but also subsets of rod bipolar, amacrine, and, in the mouse but not in the rabbit, ganglion cells. The processes of immunoreactive cell bodies form discrete bands in the internal plexiform layer, and mixtures of the antisera help distinguish their identity. Thus, these Purkinje cell markers can be used at the electron microscopic level to unravel the extremely complex neuropil of this retinal layer. Furthermore, knowledge of the retinal distribution of this panel of molecules is of general value for future studies of retinal neuronal typology and can serve to map the densities of subsets of bipolar cells throughout the retina. The expression of L7 and PEP19 in bipolar cells and in Purkinje cells suggests a biochemical relationship between these two spatially distant neuronal populations.

Animals↗
PubMed1991

Precerebellin is a cerebellum-specific protein with similarity to the globular domain of complement C1q B chain.

The cerebellum contains a hexadecapeptide, termed cerebellin, that is conserved in sequence from human to chicken. Three independent, overlapping cDNA clones have been isolated from a human cerebellum cDNA library that encode the cerebellin sequence. The longest clone codes for a protein of 193 amino acids that we term precerebellin. This protein has a significant similarity (31.3% identity, 52.2% similarity) to the globular (non-collagen-like) region of the B chain of human complement component C1q. The region of relatedness extends over approximately 145 amino acids located in the carboxyl terminus of both proteins. Unlike C1q B chain, no collagen-like motifs are present in the amino-terminal regions of precerebellin. The amino terminus of precerebellin contains three possible N-linked glycosylation sites. Although hydrophobic amino acids are clustered at the amino terminus, they do not conform to the classical signal-peptide motif, and no other obvious membrane-spanning domains are predicted from the cDNA sequence. The cDNA predicts that the cerebellin peptide is flanked by Val-Arg and Glu-Pro residues. Therefore, cerebellin is not liberated from precerebellin by the classical dibasic amino acid proteolytic-cleavage mechanism seen in many neuropeptide precursors. In Northern (RNA) blots, precerebellin transcripts, with four distinct sizes (1.8, 2.3, 2.7, and 3.0 kilobases), are abundant in cerebellum. These transcripts are present at either very low or undetectable levels in other brain areas and extraneural structures. A similar pattern of cerebellin precursor transcripts are seen in rat, mouse, and human cerebellum. Furthermore, a partial genomic fragment from mouse shows the same bands in Northern blots as the human cDNA clone. During rat development, precerebellin transcripts mirror the level of cerebellin peptide. Low levels of precerebellin mRNA are seen at birth. Levels increase modestly from postpartum day 1 to 8, then increase more dramatically between day 5 and 15, and eventually reach peak values between day 21 and 56. Because cerebellin-like immunoreactivity is associated with Purkinje cell postsynaptic structures, these data raise interesting possibilities concerning the function of the cerebellin precursor in synaptic physiology.

Amino Acid Sequence↗
PubMed1990

A promoter that drives transgene expression in cerebellar Purkinje and retinal bipolar neurons.

A genomic clone encoding the Purkinje cell-specific L7 protein has been isolated and utilized to drive the expression of beta-galactosidase in mice. Three independent transgenic lines, germ line transformed with an L7-beta-galactosidase fusion gene, exhibit beta-galactosidase expression in both cerebellar Purkinje cells and retinal bipolar neurons. This distribution is the same as that previously determined for the L7 protein by immunohistochemistry. The transgenic murine lines can be used to obtain populations of marked Purkinje and bipolar neurons. Similar L7 promoter constructs can be used to express other foreign genes specifically in these two classes of neurons.

Animals↗
PubMed1988

A Purkinje cell differentiation marker shows a partial DNA sequence homology to the cellular sis/PDGF2 gene.

To search for genes involved in determining the morphology of individual neuronal types, a cDNA library was constructed from postnatal day 13 mouse cerebellum. From this library, 2 clones, L7 and L19, were isolated by a differential hybridization procedure and shown by in situ hybridization to be Purkinje cell-specific within the cerebellum. Both RNAs appear between postnatal days 4 and 8 and continue into adulthood, coinciding with terminal differentiation of the Purkinje cells. L7 seems to be expressed exclusively in the cerebellum, whereas L19 is expressed throughout the brain. Consistent with the RNA localization, L7 protein is found only in the cerebellum and is confined to the Purkinje cells. The L7 amino acid sequence has been deduced from the cDNA sequence, and a pseudo-repeat within the L7 protein sequence is homologous to the amino acids sequence in the primary translation product of the gene for human sis/PDGF.

Amino Acid Sequence↗
PubMed1984

Immunoaffinity purification of bovine factor VII.

Factor VII has been purified to homogeneity from bovine plasma by a procedure that includes affinity purification on an immunoadsorbent column. Recovery was determined by both coagulant assay and liquid scintillation counting, using 3H-factor VII as an internal standard. The purification factor calculated by both methods was approximately 120,000-fold, with a final yield of approximately 18%. Homogeneity was assessed by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The material migrated as a single polypeptide chain of 53,000 daltons, and following activation by factor Xa, the one-chain zymogen was quantitatively converted to two-chain factor VIIa. Conversion of affinity-purified factor VII to factor VIIa resulted in up to a 119-fold activation of the coagulant activity, which is 2.7-4 times greater than the activatability reported for factor VII prepared by other methods. Zur et al. calculated that pure factor VII, uncontaminated by traces of factor VIIa, would be activated 123-fold upon conversion to factor VIIa. The close agreement between observed activatability of affinity-purified factor VII and the theoretical prediction suggests that we have isolated factor VII essentially free of factor VIIa. The purification data from three lots of bovine plasma yield an estimate for the plasma concentration of factor VII from 10.1 nM to 18.5 nM.

Animals↗
PubMedDate not supplied

Subcellular localization of specific mRNAs and their protein products in Purkinje cells by combined fluorescence in situ hybridization and immunocytochemistry.

In this study we have investigated the subcellular distribution of two mRNAs coding for the Purkinje cell-specific proteins, calbindin D28K and L7 (L7/pcp-2). Whereas calbindin mRNA was found to be in the cell body only, L7 transcripts could be detected within the molecular layer, corresponding to Purkinje cell dendrites. We have now combined a highly sensitive fluorescence-based in situ hybridization protocol with immunofluorescence in conjunction with confocal optical sectioning to analyze the precise localization of these mRNAs in individual Purkinje neurons. We show that L7 mRNA is localized in clusters within the proximal and distal branches of dendrites, but also in the proximal part of Purkinje cell axons. In contrast, calbindin transcripts are restricted to the axonal pole of the perikaryon. Purkinje cells grown in primary cultures reveal similar mRNA distribution patterns for the two transcripts. Thus, the mechanism underlying localization of mRNA within Purkinje cells seems to function in a cell-intrinsic manner, guiding specific transcripts, such as L7 mRNA, to neuronal processes while restricting others, such as calbindin mRNA, to the perikaryon.

Alkaline Phosphatase↗