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R S Peterson

Publications and source records attributed to R S Peterson.

14 recordsLinked to original sources
PubMed2001

Rapid upregulation of aromatase mRNA and protein following neural injury in the zebra finch (Taeniopygia guttata).

The expression of aromatase (oestrogen synthase) within the vertebrate central nervous system (CNS) is key in the provision of local oestrogens to neural circuits. Aromatase expression appears to be exclusively neuronal under normal conditions. However, some in vitro studies suggest the presence of astrocytic aromatase in songbirds and mammals. Recently, aromatase in reactive astrocytes has been demonstrated in response to neural injury in the mammalian CNS. Since the glial aromatase expression first documented in cultures of the songbird telencephalon may reflect processes similar to those in response to mammalian neural injury, we investigated whether injury alters the pattern of aromatase-expression in the zebra finch, a species with very high levels of forebrain aromatase expression. Adult males received a penetrating neural injury to the right hemisphere and were killed either 24 or 72 h later. Controls were anaesthetized and otherwise unmanipulated. We determined the expression of aromatase mRNA and protein using in situ hybridization and immunocytochemistry, respectively. Both the transcription and translation of aromatase is dramatically upregulated around the lesion site in response to neural injury in the zebra finch forebrain. This effect is robust and rapid, occurring within 24 h of the injury itself. Cells that upregulate aromatase appear to be reactive astrocytes based upon morphology. The hemisphere contralateral to the injury and both hemispheres in control birds showed the normal, exclusively neuronal pattern of aromatase expression. The upregulation of aromatase in astrocytes may provide high levels of oestrogen available to modulate processes such as CNS repair. Injury-induced upregulation of astrocytic aromatase may be a general characteristic of the injured vertebrate brain.

Animals↗
PubMed2000

Task conflict and relationship conflict in top management teams: the pivotal role of intragroup trust.

Task conflict is usually associated with effective decisions, and relationship conflict is associated with poor decisions. The 2 conflict types are typically correlated in ongoing groups, however, which creates a prescriptive dilemma. Three explanations might account for this relationship--misattribution of task conflict as relationship conflict, harsh task conflict tactics triggering relationship conflict, and misattribution of relationship conflict as task conflict. The authors found that intragroup trust moderates the relationship between task conflict and relationship conflict in 70 top management teams. This result supports the "misattribution of task conflict" explanation. The authors also found a weak effect that is consistent with the argument that tactical choices drive the association between the 2 conflict types. We infer that trust is a key to gaining the benefits of task conflict without suffering the costs of relationship conflict.

Adult↗
PubMed1997

The winged helix transcriptional activator HFH-3 is expressed in the distal tubules of embryonic and adult mouse kidney.

The hepatocyte nuclear factor-3 (HNF-3)/fork head homolog (HFH) proteins are an extensive family of transcription factors, which share homology in the winged helix DNA binding domain. Members of the HFH/winged helix family have been implicated in cell fate determination during pattern formation, in organogenesis, and in cell-type-specific gene expression. In this study we isolated a full-length HFH-3 cDNA clone from a human kidney library which encoded a 351-amino acid protein containing a centrally located winged helix DNA binding domain. We demonstrate that HFH-3 is a potent transcriptional activator requiring 138 C-terminal residues for activity. We used in situ hybridization to demonstrate that HFH-3 expression is restricted to the epithelium of the renal distal convoluted tubules. We determined the HFH-3 DNA binding consensus sequence by in vitro DNA binding site selection using recombinant HFH-3 protein and used this consensus sequence to identify putative HFH-3 target genes expressed there. These putative HFH-3 target genes include the Na/K-ATPase, Na/H and anion exchangers, E-cadherin, and mineralocorticoid receptor genes as well as genes for the transcription factors HNF-1, vHNF-1, and HNF-4.

Aging↗
PubMed1997

The winged helix transcriptional activator HFH-8 is expressed in the mesoderm of the primitive streak stage of mouse embryos and its cellular derivatives.

The hepatocyte nuclear factor 3/fork head homolog (HFH) proteins are an extensive family of transcription factors which share homology in the winged helix DNA binding domain. Members of the winged helix family have been implicated in cell fate determination during pattern formation, in organogenesis and in cell type-specific gene expression. In this study, we used in situ hybridization to identify the cellular expression pattern of the winged helix transcription factor, HFH-8, during mouse embryonic development. We showed that HFH-8 expression initiates during the primitive streak stage of mouse embryogenesis in the extraembryonic mesoderm and in the lateral mesoderm which gives rise to the somatopleuric and splanchnopleuric mesoderm. During organogenesis, HFH-8 expression is found in the splanchnic mesoderm in close apposition of the gut endoderm, suggesting a role in mesenchymal-epithelial induction of lung and gut morphogenesis. HFH-8 expression continues in lateral mesoderm-derived tissue throughout mouse development. HFH-8 expression is observed in the mesenchymal cells of the oral cavity, esophagus, trachea, lung, intestine, dorsal aorta and intersomitic arteries, but not in the vasculature of the head, liver, kidney or heart. Consistent with these embryonic expression studies, adult HFH-8 expression is restricted to the endothelium and connective fibroblasts of the alveolar sac and in the lamina propria and smooth muscle of the intestine. We also show that several adult endothelial cell lines maintain abundant HFH-8 expression. Furthermore, we used our determined HFH-8 consensus sequence to identify putative target genes expressed in pulmonary and intestinal mesenchymal cells. Cotransfection assays with one of these target promoters, P-selectin, demonstrated that HFH-8 expression was required for IL-6 stimulation of P-selectin promoter activity and suggest that HFH-8 is involved in mediating its cell-specific transcriptional activation in response to cytokines.

Animals↗
PubMed1997

Hepatocyte nuclear factor-3 alpha promoter regulation involves recognition by cell-specific factors, thyroid transcription factor-1, and autoactivation.

The hepatocyte nuclear factor-3 alpha (HNF-3 alpha) and -3 beta proteins share homology in the winged helix/fork head DNA binding domain and regulate cell-specific transcription in hepatocytes and respiratory epithelium. In this study, we used transfection assays to demonstrate that the -520 nucleotides upstream of the rat HNF-3 alpha gene were sufficient for cell-specific expression. We identified binding sites for a liver and kidney-enriched nuclear factor and a kidney-enriched protein that recognizes two distinct promoter elements. We showed that the rat HNF-3 alpha promoter binds the HNF-3 protein isoforms, which may serve an auto- and/or cross-regulatory role. Furthermore, we showed that cotransfection of the thyroid transcription factor-1 expression vector enhanced HNF-3 alpha promoter activity. We discuss these results with respect to the transcriptional induction of the HNF-3 alpha gene in respiratory epithelium during embryogenesis. Because the HNF-3 alpha promoter region bound nuclear factors in kidney extracts, we used in situ hybridization to demonstrate that it was expressed in the urothelium of the renal pelvis in adult and embryonic kidney. We also report on a novel expression pattern of HNF-3 alpha in the epithelium of the urinary bladder, penile urethra, and the prostate gland, and show that its expression in the intestinal epithelium increases from the proximal duodenum to distal ileum. We also demonstrate that HNF-3 alpha is abundantly expressed in the colonic epithelium. Furthermore, we use the HNF-3 DNA binding consensus sequence to identify putative target genes in the renal pelvis and gut epithelium.

Animals↗
PubMed1994

Members of the HNF-3/forkhead family of transcription factors exhibit distinct cellular expression patterns in lung and regulate the surfactant protein B promoter.

The hepatocyte nuclear factor-3 (HNF-3)/forkhead (fkh) proteins consist of an extensive family of tissue-specific and developmental gene regulators which share homology within the winged helix DNA binding motif. We report on the isolation of a new family member, HNF-3/forkhead homolog 8 (HFH-8), from lung cDNA libraries and the derivation of the complete amino acid sequences for the HFH-8 protein as well as previously identified HFH-1 and HFH-4 proteins. The HFH proteins contain several sequence motifs found in activation domains of other transcription factors and HNF-3/fkh family members. In situ hybridization with the HNF-3, HFH-4, and HFH-8 probes in adult lung demonstrate that the HNF-3/fkh cellular expression patterns are regionally specified. Whereas HNF-3 alpha and HNF-3 beta are normally coexpressed in the hepatocyte, their expression patterns in the lung are different. The HNF-3 alpha and HFH-4 genes are coexpressed in the bronchiolar epithelium (clara cells), whereas the HNF-3 beta probe exhibits prominent hybridization with the smooth muscle surrounding arterioles and bronchioles. In contrast, HFH-8 probes labeled the type II pneumocyte cells lining the respiratory surfaces of terminal bronchioles and alveolar sac. We have identified an HNF-3 consensus DNA binding sequence in the proximal surfactant protein B (SPB) promoter region (SPB-f2, -78 to -88). SPB gene transcription is restricted to bronchiolar and alveolar epithelium which colocalizes with the expression pattern of the HNF-3 alpha and HFH-8 genes, respectively. We show that the SPB-f2 sequence is recognized by both HNF-3 alpha and HFH-8 proteins and that these cDNA expression vectors activate the SPB promoter in cotransfection assays through the HNF-3 consensus sequence. Our results suggest that SPB promoter activity is regulated by HNF-3 alpha and HFH-8 proteins in a cell type-specific manner.

Aging↗
PubMed1969

Dialects in elephatn seals.

Threat vocalizations of male elephant seals Mirounga angustirostris vary among four populations on islands off the coast of California and Baja California, Mexico. Males at San Nicolas Island in Southern California emit sound pulses at more than double the rate of males at Aũo Nuevo Island, 528 kilometers north. Mean pulse rates at San Miguel Island and Isla de Guadalupe (408 and 944 kilometers south of Aũo Nuevo, respectively) are intermediate to these two. Pulse rate is homogeneous within each population and consistent in the same individual. Other properties of the calls which separate populations are pulse duration and embellishment of the initial or terminal pulse in a series. These geographical differences in vocal behavior resemble local dialects in birds and humans.

Acoustics↗