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R Hen

Publications and source records attributed to R Hen.

123 records · Page 7Linked to original sources
PubMed1983

Far upstream sequences are required for efficient transcription from the adenovirus-2 E1A transcription unit.

We have investigated the requirement for sequences located upstream from the TATA box for efficient transcription from the Adenovirus-2 (Ad2) E1A promoter. A series of deletions located within the E1A promoter upstream sequences were introduced into recombinants which contain or do not contain the E1A structural sequences. The amount of E1A-specific RNA produced after transfection into HeLa cells was determined by quantitative S1 nuclease analysis. We demonstrate that sequences located more than 231 bp upstream from the E1A capsite are required for efficient transcription from the E1A promoter. However, the requirement for these stimulatory sequences is less pronounced in recombinants which contain the E1A structural sequences than in those in which these sequences have been deleted. We demonstrate also that these Ad2 stimulatory sequences activate transcription in cis when inserted upstream from the heterologous -34 to +33 Ad2 major late promoter (Ad2MLP) element which is otherwise inactive when transfected into HeLa cells. These results suggest that the 270 bp Ad2 left-terminal segment contains an enhancer-like element.

Adenoviruses, Human↗
PubMed1983

An enhancer element is located 340 base pairs upstream from the adenovirus-2 E1A capsite.

A chimeric recombinant, containing the 270 bp left-terminal fragment of Adenovirus-2 (Ad2) inserted upstream from the -34 to +33 Ad2 major late promoter (Ad2MLP) element, has been used to characterize the transcription stimulatory element which is located at least 231 bp upstream from the E1A capsite in the left-end of Ad2 (Ref. 1). We demonstrate that this element, which acts in cis, possesses several properties characteristic of transcriptional enhancers. Firstly, it potentiates initiation of transcription from the capsite of the heterologous Ad2MLP and from "cryptic" sites often preceded by TATA box-like sequences. Secondly, although there is no critical distance requirement between the enhancer element and the Ad2MLP, the extent of stimulation decreases as the distance between the two element increases. However, in contrast to the other known viral or cellular enhancers which are bidirectional, the Ad2 enhancer is unidirectional, i.e. it potentiates the Ad2MLP element only when it is inserted in its "natural" orientation with respect to the direction of transcription. Using two convergent series of deletions, we have localized the Ad2 enhancer element within a 24 bp segment located at approximately 160 bp from the Ad2 left-end, i.e. 340 bp upstream from the E1A capsite. This 24 bp segment contains a sequence which exhibits a striking homology with the consensus sequence of several viral and cellular enhancers.

Adenoviruses, Human↗
PubMed1982

Sequences upstream from the T-A-T-A box are required in vivo and in vitro for efficient transcription from the adenovirus serotype 2 major late promoter.

We show that sequences located upstream from the T-A-T-A box, between positions -97 and -34, are necessary for efficient in vivo transcription from the adenovirus serotype 2 major late promoter. The effect of these upstream sequences was also investigated in vitro using a whole cell or an S100 extract and circular or linear templates. With the whole cell extract, the in vivo effect of the upstream sequences was reproduced in vitro. With the S100 extract, some effect of the upstream sequences was observed with circular, but not with linear, templates.

Adenoviruses, Human↗
PubMed1981

The SV40 72 base repair repeat has a striking effect on gene expression both in SV40 and other chimeric recombinants.

By introduction of recombinant plasmids into monkey CV1 cells, we have unambiguously demonstrated that sequences entirely within the 72 bp repeat, which is located upstream of the SV40 early region, are crucial for T-antigen expression in vivo. We have also shown that a DNA fragment containing the 72 bp repeat, inserted directly before chicken conalbumin or adenovirus-2 major late promoter sequences in chimeric plasmids where these promoters replace that of the SV40 early genes, caused a dramatic increase in the expression of T-antigen in vivo. This effect was independent of the orientation of the 72 bp repeat, but was sensitive to its location within the plasmid, when the 72 bp repeat was separated from the promoter sequences, T-antigen expression was reduced. Insertion of the 72 bp repeat into equivalent plasmids containing no known eukaryotic promoter sequences (plasmids which were not detectably expressed in vivo) gave rise to a measurable, but smaller level of expression. The stimulation of expression by the 72 bp repeat is cis-acting : it required covalent linkage to the recombinant. We discuss the possibility that the 72 bp repeat region in SV40 may act as a bi-directional entry site for RNA polymerase B such that promoter sequences linked to the repeat are more efficiently utilised.

Animals↗
PubMed1979

Organization and sequence studies of the 17-piece chicken conalbumin gene.

The conalbumin gene has been cloned and shown to consist of at least 17 exons approximately 60-200 base pairs long. The DNA sequence upstream from the region coding for the 5' end of the mRNA shows similarities with sequences present in homologous positions in other genes. High and low frequency repetitive sequences are found both upstream from the conalbumin gene and within one intron.

Animals↗
PubMed1978

Sequential changes of regional circulation in cerebral infarction.

Sequential changes of regional cerebral circulation and effects of spontaneous recanalization of occluded artery on cerebral circulation were observed in 50 patients with cerebral infarction. 1) Luxury perfusion was predominantly recognized in the recanalized patients within 16 days after onset. 2) Impairment of vasomotor responses was almost the same in the recanalized patients and the occluded patients. 3) CO2 response tended to recover about 3-4 weeks after onset, but disautoregulation to induced hypertension persisted up to 2 months after onset. Some clinical problems are discussed.

Adult↗
PubMed1978

[Cerebral hemodynamics in the vegetative state patients--relationship between patterns of dysautoregulation and prognosis (author's transl)].

The pathophysiological analysis of cerebral hemodynamic mechanisms and its metabolism in the vegetative patients was not enough until now. It was reported in this paper that the correlation between cerebral hemodynamics, metabolism and neurological function was analysed in 14 patients with vegetative state caused by cerebrovascular disorders. The materials consist of 14 vegetative patients due to 7 hypertensive intracerebral hemorrhage, 6 subarachnoid hemorrhage and one cerebral infarction. In all of them, the cerebral hemodynamics such as cerebral blood flow (CBF), CO2 reactivity and autoregulation, and cerebral metabolism were measured sequencially by 133Xe clearance methods. In the majority of cases, both values of mean hemispheric CBF and cerebral oxygen consumption (CMRO2) were markedly decreased with severe impairments of autoregulation and CO2 reactivity on the bilateral hemispheres but much more significatly on the affected hemispheres. Futhermore, from view points of the pressureflow relationship in the CBF studies, the patterns of dysautoregulation could be classified into 2 types as follows; Type 1 is the complete loss type, which has no plateau formation in all ranging of systemic arterial blood pressure (SABP). Type 2 is the incomplete loss type with 2 subdivisions, in which the abnormal narrowing plateaus are recognized in relatively higher or lower range of SABP (called as the upper or the lower type of incomplete loss type respectively). And then, the phenomen, which we gave a term as "shift-off phenomenon", was recognized in 8 cases that the proper values of resting SABP was seated outside the plateau level of the auto-regulatory capacity. The correlation between CBF dynamics and the grade of vegetative state was analysed. In 2 cases with slight communications (vegetative grade1), mean hemispheric CBF value was 32.5 (ml/100 g/min.) and CMRO2 was 2.01 (ml/100 g/min.) with the normal or the upper type in incomplete loss of dysautoregulation. In 3 cases of vegetative grade 2, who could slightly response to vocal order, mean CBF and CMRO2 showed 27.0 +/- 2.0 and 1.7 +/- 0.08 respectively. In these cases, dysautoregulations with the upper type incomplete loss were recognized. In 3 cases of vegetative grade 3, who had only spontaneous movement of body and slight emotional expression but no response to vocal order, mean CBF was in 22.4 +/- 1.9 and CMRO2 in 1.28 +/- 0.21. The patterns of dysautoregulation showed the lower type of incomplete loss. We had experienced the shift-off phenomenon in all of 5 cases with the upper type of incomplete loss and in 3 of 7 cases with the lower type of incomplete loss dysautoregulation. As conclusion, in cases of vegetative grade 2 or 3 whose patterns of dysautoregulation are the upper or lower type of incomplete loss with the shift-off pnenomenon, it would be a useful therapeutic method to get away from vegetative state that SABP could be corrected and controlled within the proper plateau level of autoregulation by the suitable administration of some vasoactive agents.

Adult↗
PubMed1976

[Congenital anomalies of cerebral artery and intracranial aneurysm].

It is well known that congenital anomalies such as polycystic kidney, aortic coarctation, Marfan syndrome, Ehler-Danlos syndrome are apt to be complicated by intracranial aneurysms. In this report we attempt to reveal the relation and incidence between cerebrovascular anomalies and intracranial aneurysms. The etiology of aneurysms has been discussed, too. 12 cases of persistent trigeminl artery, 2 cases of persistent hypoglossal artery and 11 cases of fenestration were obtained from 3841 patients who were angiographically examined in our clinic for 5 years. The incidence is 0.31%, 0.05% and 0.29%, respectively. Persistent trigeminal arteries were complicated by 2 cases of intracranial aneurysms and one case of arterivenous malformations (AVM), persistent hypoglossal arteries were complicated by one case of aneurysm, and fenestrations were complicated by 2 cases of aneurysms and one case of AVM. One case of congenital agenesis of right internal carotid artery was obtained which was complicated by aneurysm of anterior communicating artery. Totally, 8 cases of aneurysms and AVM were obtained from 26 cases of cerebrovascular anomalies (incidence 30.8%). On the other hand, thalamic or caudate hemorrhage revealed the highest incidence of complication of intracranial aneurysms among intracerebral hematomas (10.7%). Compared with the incidence of aneurysms between cerebro vascular anomalies (30.8%) and thalamic or caudate hemorrhage (10.7%), the difference is statistically signigicant (P less than 0.05). The cause of intracranial aneurysm has not yet been clarified. But it is well accepted that the defect of tunica media vasorum is most responsible factor as to the occurrence of intracranial aneurysms. We concluded that the genetic error of cerebral vessels including defect of media caused intracranial aneurysms, and this result was supported from the evidence that cerebrovascular anomalies showed statistically high incidence of complication of intracranial aneurysms.

Humans↗
PubMedDate not supplied

Male and female 5-HT(1B) receptor knockout mice have higher body weights than wildtypes.

5-HT(1B) receptors have a regulatory role in serotonergic activity and influence feeding behavior and body weight. Because the absence of 5-HT(1B) receptors may cause changes in this regulation, body weight was measured in male and female 5-HT(1B) receptor knockout (5-HT(1B) KO) and wildtype (WT) mice from weaning until the age of 30 weeks. In both genders, 5-HT(1B) KO mice had a higher body weight than WT mice (17% and 9%, respectively). Body weight was significantly higher for males over the entire period and for females from Week 18 onwards. Absolute food and water consumption were related to body weight. However, relative to body weight, males consumed more than females. 5-HT(1B) KO males drank strikingly more water. Housing mice singly reduced food and water intake in males, but not in females. Plasma leptin levels and most organ weights did not differ between genotypes, indicating that higher body weight in 5-HT(1B) KO mice is not related to obesity. Relative to body weight, brains and adrenals were larger in females, while heart and liver were smaller. Kidneys were smaller in females, but larger in 5-HT(1B) KO mice, while lungs showed opposite effects. Spleen and testes were smaller in 5-HT(1B) KO mice. Although 5-HT(1B) KO males are more aggressive, testosterone levels were not different from WT mice. Basal corticosterone levels were similar in all groups and increased in response to mild stress, particularly in females. Lifelong absence of 5-HT(1B) receptors in mice resulted in clear phenotypic differences in body weights and food and water intake. Lacking this receptor increases body growth, without signs of obesity. A potential genetic background effect influencing this phenotype is discussed.

Animals↗
PubMedDate not supplied

Adenovirus-2 E1A products repress enhancer-induced stimulation of transcription.

The adenovirus-2 early region 1A (E1A) products repress activation of transcription induced by the simian virus 40, polyoma virus and adenovirus-2 E1A enhancers. The repression probably involves an interaction between the enhancer elements and a trans-acting factor(s), possibly the E1A products themselves.

Adenoviruses, Human↗
PubMedDate not supplied

A mutated polyoma virus enhancer which is active in undifferentiated embryonal carcinoma cells is not repressed by adenovirus-2 E1A products.

Enhancers stimulate transcription of several eukaryotic genes (for review see ref. 1). While some enhancers, like that of simian virus 40 (SV40), are active in a wide range of cell types, others are more cell-specific. For example, the polyoma virus (Py) enhancer is not active in undifferentiated embryonal carcinoma (EC) cells, such as F9 cells, while it is active in differentiated cells. In contrast, the SV40 enhancer is active in both undifferentiated and differentiated EC cells. One possible explanation for this difference is that the two viral enhancers interact with different positively or negatively acting transcription factors, a notion supported by in vitro experiments showing that the Py enhancer interacts with proteins that do not bind to the SV40 enhancer. Some viral and cellular enhancers, including the Py and SV40 enhancers, can be negatively regulated by the products of the E1A transcription unit of adenovirus-2. As it has been postulated that undifferentiated F9 cells contain an E1A-like activity, it is possible that the latter is responsible for the lack of activity of the Py enhancer in these cells. We show here that the E1A products do not repress a point mutant of the Py enhancer (Py ECF9.1; ref. 11 and references therein) that is active in undifferentiated F9 cells. This result is consistent with the idea that undifferentiated F9 cells contain a cellular repressor that blocks the Py enhancer and that this repressor has the same target sequence as the E1A proteins.

Adenovirus Early Proteins↗