Isolation and genomic analysis of the rat polymeric immunoglobulin receptor gene terminal domain and transcriptional control region.

The polymeric immunoglobulin receptor (pIgR) transports IgA and IgM across secretory epithelial cells and is essential in external immunity maintenance. We report here the structural characterization of the single-copy rat gene distributed over 30 kb of chromosomal DNA and analysis of its transcriptional control region. RNA sequencing and genomic analysis show a 5' terminal region originates at a major (+1) and a minor site producing an unusual 124-bp nontranslated exon I separated from a small 96-bp initiator ATG coding exon II by a 7.

Mutational analysis of the RNA-fork model of the influenza A virus vRNA promoter in vivo.

The genome of influenza A virus consists of eight negative-stranded RNA segments which have partially complementary non-coding terminal sequences. Previous transcription studies of the virion RNA promoter in vitro have shown that the 5' terminus forms an integral part of the promoter and an 'RNA-fork' model has been proposed for the initiation of transcription. According to this model part of the promoter is formed by an RNA-duplex which involves complementary residues 10 to 1 2 of the 3' end and residues 11' to 13' of the 5' end.

Involvement of phospholipid molecular species in controlling structural order of vertebrate brain synaptic membranes during thermal evolution.

Fluorescence anisotropy parameter of [p-(6-phenyl)-1,3,5-hexatrienyl]phenyl-propionic acid (DPH-PA) and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) embedded in synaptic plasma membranes prepared from brains of cold (5 degrees C) and warm (22 degrees C) adapted fish (Cyprinus carpio L.), rat (Rattus norvegicus) and bird (Branta canadensis), was studied. Fatty acid composition of total lipids as well as molecular species composition of diacyl phosphatidylcholines and phosphatidylethanolamines was also determined.

Racial differences in occupational status and income in South Africa, 1980 and 1991.

Using data on employed men from the 1980 and 1991 South African Censuses, we analyze the determinants of occupational status and income. Whites are found to have much higher occupational status, and especially income, than members of other racial groups. Most of the racial differentials in occupational status con be explained by racial differences in the personal assets that determine occupational attainment (especially education), but only a much smaller fraction of the White/non-White income differential can be so explained.

Molecular architecture and biophysical properties of phospholipids during thermal adaptation in fish: an experimental and model study.

Phospholipids from livers of carps (Cyprinus carpio L.) adapted to winter (5 degrees C) and summer (25 degrees C) temperatures were isolated, and the fatty acid composition of total phospholipids, as well as molecular species composition of diacyl phosphatidylcholines and ethanolamines, were determined. Order parameter of 5-doxyl stearic acid and steady-state fluorescence anisotropy of different anthroyloxy fatty acids--[2-, 12(N-9-anthroyloxy)stearic acid and 16(N-9-anthroyloxy)palmitic acid--embedded in native and synthetic (16:0/16:0, 16:0/22:6, 18:0/22:6, 18:1/22:6, 20:4/20:4, 22:6/22:6 phosphatidylcholines and 16:0/18:1, 18:1/22:6 phosphatidylethanolamines) phospholipid vesicles was also determined between -30 and 30 degrees C and 5 and 30 degrees C, respectively.

In vitro transcription and polymerase binding studies of the termini of influenza A virus cRNA: evidence for a cRNA panhandle.

An in vitro transcription assay was used to study transcription from synthetic RNA corresponding to the 3' terminus of influenza A virus cRNA. Micrococcal nuclease-treated influenza virus ribonucleoprotein was used as a source of active polymerase complex. Mutations at two regions of the 13 nucleotide-long conserved cRNA 3' terminus were shown to reduce transcription templated by the short added model RNAs.

Solid phase synthesis of 5'-diphosphorylated oligoribonucleotides and their conversion to capped m7Gppp-oligoribonucleotides for use as primers for influenza A virus RNA polymerase in vitro.

We have synthesized four different 5'-diphosphorylated oligoribonucleotides, varying in length from 11 to 13 nucleotides by a new solid phase method. After deprotection and partial purification the 5'-diphosphorylated oligoribonucleotides could be converted to capped (m7Gppp) oligoribonucleotides using guanylyl transferase. Radiolabelled capped oligoribonucleotides acted as primers for the influenza A virus RNA polymerase in vitro.

Characterization of the RNA-fork model of virion RNA in the initiation of transcription in influenza A virus.

It has been shown that both 3' and 5' conserved termini of influenza A virus virion RNA are involved in the initiation of transcription. An RNA-fork model has been proposed, according to which there is a crucial double-stranded region formed by complementary bases at positions 10 to 12 of the 3' terminus and bases at positions 11' to 13' of the 5' terminus, which are extended by 2 or 3 segment-specific base pairs. The two termini at positions 1 to 9 and 1' to 10' in the 3' and 5' termini, respectively, are in a single-stranded conformation.

Discordant expression and variable numbers of neighboring GGA- and GAA-rich triplet repeats in the 3' untranslated regions of two groups of messenger RNAs encoded by the rat polymeric immunoglobulin receptor gene.

An unusual S1-nuclease sensitive microsatellite (STMS) has been found in the single copy, rat polymeric immunoglobulin receptor gene (PIGR) terminal exon. In Fisher rats, elements within or beyond the STMS are expressed variably in the 3' untranslated regions (3'UTRs) of two 'Groups' of PIGR-encoded hepatic mRNAs (pIg-R) during liver regeneration. STMS elements include neighboring constant regions (a 60-bp d[GA]-rich tract with a chi-like octamer, followed by 15 tandem d[GGA] repeats) that merge directly with 36 or 39 tandem d[GAA] repeats (Fisher or Wistar strains, respectively) interrupted by d[AA] between their 5th-6th repeat units.

Liver expression of epidermal growth factor RNA. Rapid increases in immediate-early phase of liver regeneration.

The liver exhibits a remarkable capacity to regenerate its mass following partial removal or after injury. Transmembrane receptors for epidermal growth factor (EGF) are highly expressed in liver cells, which quickly respond to this polypeptide mitogen by activating an intrinsically low rate of cell division. Although EGF appears to regulate liver growth, its significance has remained unclear, and only a small change in serum levels can be detected during hepatocellular proliferation.

The influenza virus panhandle is involved in the initiation of transcription.

The role of the influenza A virus panhandle structure formed from the 3'- and 5'-terminal nucleotides of virion RNA segments was studied in both an RNA polymerase binding assay and an in vitro transcription assay. Despite recent indications that promoter activity is simply a function of the 3'-terminal sequence of virion RNA, our results show that both 3'- and 5'-terminal sequences are involved in the initiation of transcription. We propose a new model for the initiation of transcription which has implications for the mechanisms by which influenza virus transcription, replication, and polyadenylation may be regulated in the infected cell.

Photochemical cross-linking of influenza A polymerase to its virion RNA promoter defines a polymerase binding site at residues 9 to 12 of the promoter.

A previous study of the 12 nucleotide-long influenza A virion RNA promoter has shown that three nucleotides, residues 9 to 11, were crucial for transcription in vitro, although other nucleotides play a significant but less important role. A model for polymerase-promoter recognition was proposed, according to which there were two sites: a binding site at residues 9 to 11 and a regulatory site at or near the site of initiation at residue 1. By studying the effect of point mutations in the promoter on the binding efficiency of the polymerase using a photochemical cross-linking assay, we now show that residues 9 to 12 are crucial for binding.

Effect of nutrients on plasma corticosteroid concentration in cold-stressed rats.

Little is known about the mechanisms as to how nutrients affect plasma corticosteroids in cold-stressed and starved animals. Therefore, cold-stressed rats (maintained at 7 degrees C) were fasted (control) or fed a balanced diet (casein 20 wt%, fat 5 wt%, starch 70 wt% and vitamin-mineral premix 5 wt%) or the following dietary nutrients for 72 h: casein, lard, starch, glycerol, stearic acid, leucine or glutamic acid. The animals were then killed and plasma corticosteroid concentrations (PCC) were determined.

Investigation of Shiga-like toxin binding to chemically synthesized oligosaccharide sequences.

Shiga-like toxin (SLT)-I and SLT-II/IIc bound to Synsorbs containing synthetic alpha Gal(1-4)beta Gal (P1 disaccharide), alpha Gal(1-4)beta GlcNAc (P1 trisaccharide), or alpha Gal(1-4)beta Gal(1-4)beta Glc (Pk trisaccharide) sequences but not to Synsorbs containing alpha Gal(1-3)beta Gal, alpha Gal(1-3)beta Gal(1-4)beta GlcNAc, or the hydrophobic oligosaccharide linkage arm. SLT-I had a preference for Synsorbs containing trisaccharides, whereas SLT-II/IIc binding was less selective. 125I-labeled SLT-I remained bound to Pk trisaccharide Synsorb in the presence of lactose, galactose, or EDTA but was partially released by acetic acid, guanidine HCl, or a 10% solution of SDS.

A pancreatic exocrine cell factor and AP4 bind overlapping sites in the amylase 2A enhancer.

A factor found in pancreatic exocrine cell lines and pancreatic nuclei binds selectively to the alpha-amylase 2A transcriptional enhancer. Pancreatic exocrine cell extracts protect asymmetrically an unusually large, 35 base pair region from DNase I digestion in vitro, suggesting the involvement of a multimeric DNA binding complex. We show that this region of the enhancer contains a major affinity recognition sequence for the HeLa transcription factor AP4.

Pan: a transcriptional regulator that binds chymotrypsin, insulin, and AP-4 enhancer motifs.

Two cDNAs were cloned that encode proteins (Pan-1 and Pan-2, with predicted molecular masses of 67.4 and 67.7 kD, respectively) that bind to a conserved transcriptional regulatory element present in pancreatic exocrine genes.

[Preventive value of vitamin D in various doses based on a prospective study of healthy infants].

Authors have kept under review two groups of healthy full-term infants born from undisturbed pregnancy, who lived in good social conditions from birth to one year of age. One of the groups was given 500IU/die and the other 1200 IU/die vitamin D. Authors evaluated the effect of the different doses of vitamin D on the prophylaxis of the rickets.

Nerve growth factor induces the proto-oncogene c-jun in PC12 cells.

Nerve growth factor (NGF) induces the rapid but transient expression of two transcripts with homology to the proto-oncogene c-jun (AP-1) in PC12 cells. The c-jun transcripts increase within 15 min after NGF addition, peak at 1 h, and decline to basal level by 4 h. Actinomycin D inhibits the increase, and cycloheximide prevents the decrease of c-jun mRNA.

A mammalian viral enhancer confers transcriptional regulation in yeast.

Transcriptional enhancers are DNA sequences that regulate RNA transcription from linked promoters by binding to cellular proteins (trans-activators). In the mammalian virus SV40, initiation of transcription is controlled, in part, by a strong 72-base pair enhancer. We show that yeast cells contain a factor that binds specifically to a key DNA motif in the SV40 enhancer, the P element that is essential for viral transcription in mammalian cells.

The human growth hormone gene contains both positive and negative control elements.

A subset of DNA sequences in the 5'-flanking DNA of the human growth hormone (hGH) gene was examined by protein-DNA binding and gene transfer-expression experiments. Two adjacent cis-acting elements (I and II) were identified between nucleotides -308/-235 of the hGH gene that modulated the expression of a linked reporter gene in transfected HeLa cells. Elements I and II repressed gene expression whereas element II alone activated it.

Capturing nuclear sequence-specific DNA-binding proteins by using simian virus 40-derived minichromosomes.

We have used recombinant simian virus 40 (SV40) minichromosomes to retrieve sequence-specific DNA-binding proteins derived from the cell nucleus of COS-7 cells. We showed that the transcription factors AP-1 and Sp1 are stably bound to the SV40 DNA late in viral infection. Under similar conditions, minichromosomes carrying the rat insulin (rINS1) enhancer, which is under negative regulation in COS-7 cells, bound two proteins which mapped to distinct regions of the rINS1 enhancer.

Cell-specific expression of heat shock proteins in chicken reticulocytes and lymphocytes.

We have found that chicken reticulocytes respond to elevated temperatures by the induction of only one heat shock protein, HSP70, whereas lymphocytes induce the synthesis of all four heat shock proteins (89,000 mol wt, HSP89; 70,000 mol wt, HSP70; 23,000 mol wt, HSP23; and 22,000 mol wt, HSP22). The synthesis of HSP70 in lymphocytes was rapidly induced by small increases in temperature (2 degrees-3 degrees C) and blocked by preincubation with actinomycin D. Proteins normally translated at control temperatures in reticulocytes or lymphocytes were not efficiently translated after incubation at elevated temperatures.

Endonuclease S1-sensitive site in chicken pro-alpha 2(I) collagen 5' flanking gene region.

A site that is preferentially cleaved by the single-strand-specific endonuclease from Aspergillus oryzae was located in vitro 180 base pairs upstream from the 5' end of the chicken pro-alpha 2(I) collagen gene. It is found in supercoiled plasmids with a negative superhelical density of -0.024 or more but not in linear DNA molecules.

The effect of pure Fusarium toxins (T-2, F-2, DAS) on the microflora of the gut and on plasma glucocorticoid levels in rat and swine.

The gut microflora and adrenal cortex hormone levels were monitored in HUNGAHYB piglets of 10-12 kg and in Wistar rats of 100-150 g body weight fed with different pure Fusarium toxins. The feeding of either T-2, T-2 + F-2 and DAS toxins at the 5 microgram/g feed level for one week resulted in the substantial increase of aerobic bacteria count of the intestine. Increase of the DAS dose to a twofold level failed to elicit dose-response and no further increases in bacterial counts were observed.