[Clinical characteristics of "classical" and "non-classical" paraneoplastic neurological syndrome]

Objective: To explore the clinical features of classical and non-classical paraneoplastic neurological syndrome (PNS). Methods: From 2015 to 2020, 48 cases of definite PNS admitted to the First Affiliated Hospital of University of Science and Technology of China were retrospectively collected, and classification, clinical characteristics, onconeural antibodies and primary tumors were analyzed. The included cases were divided into classical and non-classical groups according to Graus criteria, and the differences of clinical characteristics, onconeural antibodies, combined tumors, time of diagnosis and mortality were compared between the two groups. Results: Among the 48 confirmed patients, 21 (43.8%) were positive for well-characterized onconeural antibodies. There were 28 cases (58.3%) and 20 cases (41.7%) in classic and non-classical PNS groups, respectively. No significant differences of age, sex, clinical involvement site, characteristic positive antibody type, tumor diagnosis rate and follow-up mortality were found between the two groups (all P>0.05). The time of diagnosis in the non-classical PNS group was 3.0 (2.0, 6.5) months, which was significantly longer than that in the classical PNS group 1.0(0.6, 3.0) months (P<0.05). Meanwhile, the combination rate of non-characteristic antibodies in the classical PNS group (10 cases, 35.7%) was significantly higher than that in the non-classical PNS group (1 case, 5.0%) (P=0.016). During the follow-up, 39 patients (81.3%) with tumor were confirmed, and 29 patients (60.4%) were diagnosed with PNS before the tumor was found. Conclusions: The"non-classical"PNSs are common in clinical settings. Diagnosis may be delayed due to the nonclassical symptoms of the patients. When patients have clinical symptoms related to PNS, onconeural antibodies should be detected and the relevant tumors should also be screened. Patients have positive antibodies but with no tumors should be closely followed up for more than 5 years.

Oncogenic activation of JAK3-STAT signaling confers clinical sensitivity to PRN371, a novel selective and potent JAK3 inhibitor, in natural killer/T-cell lymphoma

Aberrant activation of the JAK3-STAT signaling pathway is a characteristic feature of many hematological malignancies. In particular, hyperactivity of this cascade has been observed in natural killer/T-cell lymphoma (NKTL) cases. Although the first-in-class JAK3 inhibitor tofacitinib blocks JAK3 activity in NKTL both in vitro and in vivo, its clinical utilization in cancer therapy has been limited by the pan-JAK inhibition activity. To improve the therapeutic efficacy of JAK3 inhibition in NKTL, we have developed a highly selective and durable JAK3 inhibitor PRN371 that potently inhibits JAK3 activity over the other JAK family members JAK1, JAK2, and TYK2. PRN371 effectively suppresses NKTL cell proliferation and induces apoptosis through abrogation of the JAK3-STAT signaling. Moreover, the activity of PRN371 has a more durable inhibition on JAK3 compared to tofacitinib in vitro, leading to significant tumor growth inhibition in a NKTL xenograft model harboring JAK3 activating mutation. These findings provide a novel therapeutic approach for the treatment of NKTL.

Effects of dietary copper on growth, digestive, and brush border enzyme activities and antioxidant defense of hepatopancreas and intestine for young grass carp (Ctenopharyngodon idella)

To investigate the effects of dietary copper (Cu) on fish growth, digestive and absorptive enzyme activities, and antioxidant status in the hepatopancreas and intestine, young grass carp (Ctenopharyngodon idella) (282±2.8 g) were fed six diets containing 0.74 (basal diet), 2.26, 3.75, 5.25, 6.70, and 8.33 mg Cu /kg diet for 8 weeks. Results showed that percentage weight gain (PWG) and feed intake were increased with dietary Cu levels up to 3.75 mg/kg diet. In addition, the positive effects of dietary Cu at a level 3.75 or 5.25 mg/kg diet on trypsin, chymotrypsin, and lipase activities in the hepatopancreas and of Na(+), K(+)-ATPase, alkaline phosphatase, creatine kinase, and γ-glutamyl transpeptidase activities in three intestine segments produced significantly (P<0.05) better feed efficiency (FE). However, amylase activity in the hepatopancreas was decreased by dietary Cu levels up to 3.75 mg/kg diet (P<0.05). In addition, dietary Cu at 3.75 or 5.25 mg/kg diet decreased malondialdehyde and protein carbonyl content partly by significantly (P<0.05) increasing the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, and glutathione content in the hepatopancreas and intestine. Collectively, dietary Cu improved growth and digestive and absorptive capacity and decreased lipid peroxidation and protein oxidation partly by enhancing antioxidant defense in the hepatopancreas and intestine. The dietary Cu requirement for PWG, plasma ceruloplasmin activity, and FE of young grass carp (282-688 g) were 4.78, 4.95, and 4.70 mg/kg diet, respectively.

[Evaluation of health education in primary school students from schistosomiasis-endemic areas around Poyang Lake by KAP hierarchical evaluation method]

OBJECTIVE

To quantitatively evaluate the intervention effect of schistosomiasis health education on the knowledge, attitude and behavior (KAP) among the primary school students.

METHODS

A questionnaire was designed to collect baseline data. Questionnairing was conducted among students of grades 3 and 4 from the Central Primary School, Liyuzhou Primary School, and Meichi Primary School in Wuxing Farm of Nanchang City in June 2010. Eighty-four students from Central Primary School were selected as experiment group, and 62 students in the other two schools served as control group. Health education intervention (knowledge lectures, information dissemination, intensive education and so on) was conducted for the students in experiment group from September 2010 to October 2011. Final KAP questionnaire survey was carried out after intervention. A KAP hierarchical evaluation method was used to calculate the KAP scores in the two groups before and after intervention.

RESULTS

After health education, the total KAP score in experiment group increased from 8.40 before education to 9.36 (t = 2.994 4, P < 0.01), higher than that of the control (8.53, t = 5.335 5, P < 0.01). The scores of knowledge, attitude and behavior of schistosomiasis control increased from 6.16, 9.10, and 8.67 before education to 8.12, 9.86, and 9.45 after education in experiment group (t = 5.716 8, P < 0.01; t = 3.2764, P < 0.01; t = 3.276 4, P < 0.01), respectively. Compared to the experiment group, after health education the scores of knowledge (6.34, t = 3.517 5, P < 0.01) and attitude of schistosomiasis control (9.43, t = 2.311 9, P < 0.05) were lower in control group; but no significant difference was found on the score of behavior between the two groups. After health education, the scores of 26 indices in experiment group were higher than that of the control and before education.

CONCLUSION

The health education intervention is effective for schistosomiasis control in the experiment school.

[Systematic surveillance of water body in schistosomiasis susceptible areas in Nanchang County by sentinel mice]

OBJECTIVE

To determine the status of cercariae of Schistosoma japonicum in water bodies of the Nanchang County section of Poyang Lake region.

METHODS

By using sentinel mice, the schistosome infectivity of water bodies was detected in 8 surveillance areas (59 experimental points in total) along the Fu River, Wuxing Farm, south branch of the Ganjiang River, and middle branch of the Ganjiang River from June to July 2011.

RESULTS

A total of 600 sentinel mice were placed in the experimental areas and 584 were retrieved, among which 577 mice were dissected and 1 mouse was infected with S. japonicum (4 worms collected), with the infection rate of 0.17%.

CONCLUSION

By using the sentinel mouse method to survey the water body schistosome infectivity, the status of Oncomelania snails should be mainly considered, and the infection rate of sentinel mice is affected by water situation, water level, flow velocity, etc.

[Spatial clustering detecting for schistosomiasis in Nanchang County]

OBJECTIVE

To explore the cluster of schistosomiasis in Nanchang County, Jiangxi Province.

METHODS

Based on the data of schistosome infection cases and population, the spatial analysis technology, global autocorrelation and hotspot detection methods in ArcGIS 9.2 software were used to render the spatial autocorrelation coefficient graph. The autocorrelation index change trend of schistosome infection rates in different spatial scales was described. In addition, the hotspot area of schistosome infection rates in study area was detected by using the representative distance for pace parameters combined with actual situation.

RESULTS

The spatial distribution of schistosome infection in study area was characteristic of clusters in 2009. The spatial autocorrelation coefficient graph indicated that the peak of wave happened in the distances of 1 900 m, 2 600 m, 3 800 m and 5 000 m, respectively. Comparing with the geographical conditions, the hotspots in 5 000 m spatial scale were more realistic than other distances. In this scale, 2 hotspots and 2 second hotspots were explored.

CONCLUSION

The spatial clustering analysis combined with the spatial autocorrelation analysis can explore the schistosomiasis gathering area more precisely.

[Evolution of spatial-temporal pattern of schistosome infection rates in Nanchang County, Jiangxi Province]

OBJECTIVE

To explore the evolution of spatial-temporal pattern of schistosome infection rates in Nanchang County, Jiangxi Province.

METHODS

Based on the data of schistosome infection rates at unit of administrative villages during 2006 to 2009, the evolution of spatial-temporal pattern of schistosome infection rates was analyzed by means of global Moran's I, Getis-Ord General G, local Getis-Ord Gi and variogram.

RESULTS

Since 2006, the global Moran's I index increased, and all the Getis-Ord General G index G (d) values were 0.02, all the Z(d) values were of statistic significance (all P values were < 0.01). The hotspots mainly distributed in the northeast and southeast of the county, while the cold spots and secondary cold spots mainly distributed in the southwest. The optimal fitted variograms of the 3 years were all Gaussian model, the Nugget coefficient decreased from 0.026 to 0.006. The spatial autocorrelation of schistosome infection rates got stronger, the ranges shrank by 9.04%.

CONCLUSION

The schistosome infection rates in Nanchang County have a tendency of clustering towards the areas along the lake, and the impact of the structural factors is increasing, but the effect range of spatial correlation is decreasing.

[Comparison of knowledge, attitude and practice of students left at home or not on schistosomiasis prevention and control]

The questionnaire survey on knowledge, attitude and practice (KAP)of students left at home or not about schistosomiasis prevention and control showed that there were no statistically significant differences of the scores of KAP between the two groups of students (all P values were above 0.05).

[Study on quality of schistosomiasis knowledge questionnaire of primary pupils in Wuxing Farm School of Nanchang City]

OBJECTIVE

To evaluate the quality of a questionnaire about schistosomiasis knowledge of the pupils in Wuxing Farm School in Nanchang City.

METHODS

The quality of the questionnaire about schistosomiasis knowledge was evaluated through reliability, validity, discrimination and some other indexes.

RESULTS

The entire reliability of the survey was high with its split-half reliability of 0.68 and Cronbach alpha coefficient of 0.627. The content validity was good: the exploratory factor analysis revealed 5 common factors from 13 questionnaire items which could account for 58.3% of the total variance; the confirmatory factor analysis revealed that the construct validity of 13 questionnaire items was better than that of the whole questionnaire (17 items in total) (chi2 = 90.5, df = 65, GFI = 0.92, AGFI = 0.88, NFI = 0.58, CFI = 0.817, RMSEA = 0.049); the difficulty and the discrimination coefficients of the questionnaire were suitable, being 0.595 and 0.42 respectively.

CONCLUSION

The questionnaire is qualified in general, but parts of the items need to be revised to perfect.

Polymorphisms of caprine POU1F1 gene and their association with litter size in Jining Grey goats

Seven pairs of primers were designed to amplify 5' promoter region, six exons and partial introns and to detect the polymorphisms of POU1F1 gene in five goat breeds with different prolificacy. The results showed that six mutations were identified in caprine POU1F1 gene including C256T in exon 3, C53T and T123G in intron 3, and G682T (A228S), T723G and C837T in exon 6. The former four mutations were novel SNPs in goat POU1F1 gene. The 53 and 123 loci were in complete linkage disequilibrium in five caprine breeds. Regarding the 256 locus, the Jining Grey goat does with genotype CT had 0.66 kids more than those with genotype CC (P < 0.05), while does with genotype GT had 0.63 (P < 0.05) kids more than those with genotype GG at the 682 locus. The present study preliminarily showed an association between allele T at the 256 and 682 loci of POU1F1 gene and high litter size in Jining Grey goats. Totally 16 haplotypes and 50 genotypes were identified at the above six loci in POU1F1 gene of five goat breeds. Three common haplotypes (hap2, hap3 and hap4) were identified in five goat breeds joined. Four specific haplotypes (hap7, hap9, hap11 and hap13) were detected in Jining Grey goats. The predominant haplotype was hap1 (35.29% and 48.25%) in both Jining Grey and Guizhou White goats, while hap4 (50%) in Boer goats, and hap2 (42.86% and 38.75%) in both Wendeng Dairy and Liaoning Cashmere goats. The most frequent genotypes at six loci in the above five goat breeds were hap1/hap2 (14.38%) and hap1/hap4 (14.38%), hap1/hap2 (38.60%), hap4/hap4 (40.91%), hap2/hap4 (26.53%), hap2/hap5 (20.00%), respectively. The Jining Grey goat does with nine genotypes analyzed of POU1F1 gene showed no obvious difference in litter size.

[Preliminary study on the comprehensive evaluation method of schistosomiasis health education--a field study in a heavy endemic area in lake region]

OBJECTIVE

To explore a comprehensive evaluation method of knowledge, attitude and behavior (KAP) about schistosomiasis control among students of susceptibility zone in lake region.

METHODS

A comprehensive KAP evaluation indicator system was developed by using analytic hierarchy process (AHP). The system consists of three layers. First-layer indices include knowledge, altitude and behavior of schistosomiasis control. 17 specific parts compose second-layer indices. Third-layer indices have 30 specific aspects. The experts were invited to provide comments for these indicators, and indicator weights were formulated by using AHP. A questionnaire survey was conducted among students of grade 3 and 4 from Central Primary School, Liyuzhou Primary School and Meichi Primary School in Wuxing Farm. Status of health education for schistosomiasis was evaluated by this method.

RESULTS

n the indicator system, the weights of behavior, altitude and knowledge were 0.54, 0.30, and 0.16, respectively. The average score of KAP indicator was 8.45. The score for behavior, altitude and knowledge indicators was 8.86, 8.90, and 6.25, respectively. The scores of some indicators such as fishing outside and inside level, washing outside level and grazing in marshland were 8.17-9.29.

CONCLUSION

This comprehensive evaluation method can be used to evaluate basic situation and effect of health education in schistosomiasis intervention. The health education should be strengthened in the survey site.

[Survey on knowledge and attitude of schistosomiasis control among villagers in susceptible zones in Poyang Lake area]

OBJECTIVE

To understand the status of health education on schistosomiasis for residents in susceptible zone and provide a reasonable basis for related study.

METHODS

A questionnaire survey on knowledge, attitude about schistosomiasis of the residents was conducted.

RESULTS

Status of education on schistosomiasis of susceptible areas for the residents in general is not optimistic, the frequency of contacting with infected water was high, the demographic characteristics were also significant: (1) The passing rate for the villagers' schistosomiasis knowledge was too low, only 39.6%, the difference between awareness rates of schistosomiasis knowledge among villagers with different educational levels was significant (P < 0.05); (2) The overall level of correct attitude for schistosomiasis control was poor, only 37.7% of the villagers with a good attitude, the differences among villagers with different ages and occupations were significant (both P values < 0.05); (3) 73.5% of the villagers had ever contacted with infected water, and different groups contacted with infected water in different ways, 67.5% of men contacting for bathing, fishing, 63.7% of women contacting for washing clothes.

CONCLUSIONS

Health education for schistosomiasis control in susceptible zones should be strengthened, the reasons for differences in cognitive level about schistosomiasis control among the villagers with different demographic characteristics and the better models for educational interventions for different villagers need to be explored.

GDF9 as a candidate gene for prolificacy of Small Tail Han sheep

Growth differentiation factor 9 (GDF9) which controls the fecundity of Belclare, Cambridge, Santa Ines, Moghani, Ghezel and Thoka ewes was studied as a candidate gene for the prolificacy of Small Tail Han sheep. According to the sequence of ovine GDF9 gene, six pairs of primers were designed to detect single nucleotide polymorphisms of two exons of GDF9 gene in both high fecundity breed (Small Tail Han sheep) and low fecundity breed (Dorset sheep) by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). Only the products amplified by primers 2-1 and 2-2 displayed polymorphisms. For primer 2-1, three genotypes (AA, AB and BB) were detected in both sheep breeds. Sequencing revealed one silent mutation (G477A) in exon 2 of GDF9 gene in the BB genotype in comparison with the AA, which was known as G3 mutation of GDF9 gene in Belclare and Cambridge ewes. The relationship of least squares means for litter size was AA > AB > BB in Small Tail Han sheep (P > 0.05). For primer 2-2, two genotypes (CC and CD) were detected in both sheep breeds. Sequencing revealed one novel single nucleotide mutation (G729T) in exon 2 of GDF9 gene in the CD genotype in comparison with the CC, which resulted in an amino acid change (Gln243His). The ewes with mutation heterozygous genotype CD had 0.77 (P < 0.01) lambs more than those with wild type CC in Small Tail Han sheep. These results preliminarily indicated that allele D of GDF9 gene was a potential genetic marker for improving litter size in Small Tail Han sheep.

Diminution of toxic copper accumulation in toxic milk mice modeling Wilson disease by embryonic hepatocyte intrasplenic transplantation

AIM: To observe the therapeutic effect of intrasplenic transplantation with embryonic hepatocytes on amelioration of hereditary copper accumulation in toxic milk (TX) mouse modeling Wilson disease.

METHODS: Donor hepatocytes were harvested from 14-d fetal liver of a pregnant homogeneous DL mouse. These cells were successively cultured, labeled with fluorescein dye Hoechst 33342 for 24 h, and sequentially infused into the spleen parenchyma of the recipient TX mice. No host immunosuppression measures were taken. Two and four weeks after transplantation, the recipients were killed for routine histologic investigation and immunohistochemistry study up to 4 wk after transplantation. The serum copper and ceruloplasmin concentrations of the recipient mice were determined by graphite furnace atomic absorption spectroscopy.

RESULTS: In the following 2^nd and 4^th wk after transplantation, the donor hepatocytes could be visualized in the livers of 47.3% recipients. The serum ceruloplasmin and copper concentrations increased by 1.6-fold after 2 wk and 2.0-fold times after 4 wk respectively, which ultimately rose from about 30% of the normal level to nearly 60% (P<0.01). The hepatic copper concentration decreased 7.2%, 4 wk after transplantation. Pathologic examination showed that there were many actively proliferative hepatocyte precursor cells with specific embryonic hepatocyte marker AFP migrated into hepatic sinusoids of the recipients. A large number of cells carrying hepatocytes marker and albumin were observed in the recipient spleen tissues.

CONCLUSION: Embryonic hepatocytes are capable of differentiating into mature hepatocytes in vivo. After transplantation, the hereditary abnormalities of copper metabolism in TX mice could be corrected partially by intrasplenic transplantation of homogeneous embryonic hepatocytes.

Role of C/EBP homologous protein (CHOP-10) in the programmed activation of CCAAT/enhancer-binding protein-beta during adipogenesis

Hormone induction of growth-arrested preadipocytes triggers mitotic clonal expansion followed by expression of CCAAT/enhancer-binding protein (C/EBP)alpha and differentiation into adipocytes. The order of these events is critical because C/EBPalpha is antimitotic and its expression prematurely would block the mitotic clonal expansion required for differentiation. C/EBPbeta, a transcriptional activator of the C/EBPalpha gene, is expressed early in the differentiation program, but lacks DNA-binding activity and fails to localize to centromeres until preadipocytes traverse the G(1)-S checkpoint of mitotic clonal expansion. Evidence is presented that dominant-negative CHOP-10 expressed by growth-arrested preadipocytes transiently sequesters C/EBPbeta by heterodimerization. As preadipocytes reach S phase, CHOP-10 is down-regulated, apparently releasing C/EBPbeta from inhibitory constraint and allowing transactivation of the C/EBPalpha gene. In support of these findings, up-regulation of CHOP-10 with the protease inhibitor N-acetyl-Leu-Leu-norleucinal prevents activation of C/EBPbeta, expression of C/EBPalpha, and adipogenesis.

Role of the CCAAT enhancer binding proteins (C/EBPs) in adipocyte differentiation

Members of the C/EBP family of transcription factors play essential roles in the adipocyte differentiation program. Treatment of growth-arrested 3T3-L1 preadipocytes with appropriate hormonal agents causes the cells to synchronously reenter the cell cycle and to undergo mitotic clonal expansion. Expression of C/EBPbeta and delta occur early in clonal expansion, later followed by C/EBPalpha (which is anti-mitotic) as the cells exit the cell cycle begin to express adipocyte genes. C/EBPalpha serves as transcriptional activator of many adipocyte genes whose expression produce the adipocyte phenotype. Recent work in this laboratory has focussed on the roles of C/EBPbeta and delta in the differentiation program, in particular the mechanisms by which they activate transcription of the C/EBPalpha gene. Several regulatory elements, both repressive and activating, in proximal promoter of the gene have been identified. The cognate transacting factors that interact with these elements have been characterized and their functions elucidated. These factors have been incorporated into a model for a cascade that leads to transcriptional activation of the C/EBPalpha gene and the terminal steps in the differentiation program.

Activation and centromeric localization of CCAAT/enhancer-binding proteins during the mitotic clonal expansion of adipocyte differentiation

Hormonal induction of 3T3-L1 preadipocytes triggers a cascade of events that initiate differentiation into adipocytes. CCAAT/enhancer-binding proteins beta and delta (C/EBPbeta/delta) are expressed early in the differentiation program, but are not immediately active. After a long lag, C/EBPbeta/delta become competent to bind to the C/EBP regulatory element in the C/EBPalpha gene promoter, C/EBPalpha being a transcriptional activator of numerous adipocyte genes. As C/EBPbeta/delta acquire binding activity, they become localized to centromeres as preadipocytes synchronously enter S phase at the onset of mitotic clonal expansion. Localization to centromeres occurs through C/EBP consensus-binding sites in centromeric satellite DNA. C/EBPalpha, which is antimitotic, becomes centromere-associated much later in the differentiation program as mitotic clonal expansion ceases and the cells become terminally differentiated.

Repressive effect of Sp1 on the C/EBPalpha gene promoter: role in adipocyte differentiation

Expression of C/EBPalpha is required for differentiation of 3T3-L1 preadipocytes into adipocytes. Previous investigations indicated that transcription of the C/EBPalpha gene is sequentially activated during differentiation, initially by C/EBPbeta and C/EBPdelta and later by C/EBPalpha (autoactivation). These events are mediated by a C/EBP regulatory element in the promoter of the C/EBPalpha gene. This article presents evidence that members of the Sp family, notably Sp1, act repressively on the C/EBPalpha promoter prior to the induction of differentiation. Sp1 was shown to bind to a GC box at the 5' end of the C/EBP regulatory element in the C/EBPalpha promoter and, in so doing, to competitively prevent binding to and transactivation of the promoter by the C/EBPs. One of the differentiation inducers methylisobutylxanthine (a cAMP phosphodiesterase inhibitor) or Forskolin, both of which increase the cellular cAMP level, causes down-regulation of Sp1. This decrease in Sp1 level early in the differentiation program appears to facilitate access of C/EBPbeta and/or C/EBPdelta to the C/EBP regulatory element and, thereby, derepression of the C/EBPalpha gene.

Derepression of the C/EBPalpha gene during adipogenesis: identification of AP-2alpha as a repressor

During adipogenesis, CCAAT/enhancer binding protein alpha (C/EBPalpha) serves as a pleiotropic transcriptional activator of adipocyte genes. Previously, we identified dual repressive elements in the C/EBPalpha gene and a putative transacting factor (C/EBPalpha undifferentiated protein, or CUP) expressed by preadipocytes, but not adipocytes, that bind to these elements. In the present investigation, CUP was purified 17,000-fold from nuclear extracts of 3T3-L1 preadipocytes. Amino acid sequence and mass spectral analysis of tryptic peptides derived from purifed CUP (molecular mass approximately 50 kDa) revealed that the repressor is (or contains) an isoform of the transcription factor, AP-2alpha. Electrophoretic mobility shift and Western blot analysis on purified CUP and preadipocyte nuclear extracts confirmed the identity of CUP as AP-2alpha. Both AP-2alpha protein and CUP binding activity are expressed by preadipocytes and then decrease concomitantly during differentiation of 3T3-L1 preadipocytes into adipocytes. Consistent with a repressive role of AP-2alpha/CUP, an AP-2alpha1 expression vector, cotransfected with a C/EBPalpha promoter-reporter construct into 3T3-L1 adipocytes, inhibited reporter gene transcription. Taken together with previous results, these findings suggest that in preadipocytes the C/EBPalpha gene is repressed by AP-2alpha/CUP, which, upon induction of differentiation, is down-regulated, allowing expression of the gene.

Repression of transcription mediated by dual elements in the CCAAT/enhancer binding protein alpha gene

During adipocyte differentiation, the expression of C/EBPalpha is activated, which in turn serves to transcriptionally activate numerous adipocyte genes. A previous search for cis elements that regulate transcription of the C/EBPalpha gene led to the identification of a potential repressive element within the proximal 5' flanking region of the gene. Nuclear extracts from 3T3-L1 preadipocytes, but not adipocytes, were found to contain a factor, CUP (C/EBPalpha undifferentiated protein), that binds to this site (the CUP-1 site). In the present investigation, we show that C/EBPalpha promoter-luciferase constructs containing both the proximal 5' flanking and the entire 5' untranslated regions of the gene exhibit an expression pattern during adipocyte differentiation comparable to that of the endogenous C/EBPalpha gene. Mutation of the CUP-1 site in these constructs had little effect on reporter gene expression; however, when this mutation was combined with deletion of the 5' untranslated region, reporter gene expression by preadipocytes was dramatically up-regulated. Consistent with this finding, a second CUP binding site (the CUP-2 site) was identified in the 5' untranslated region. Although mutation of either CUP element in constructs containing both the 5' flanking and 5' untranslated region had little effect on reporter gene transcription, mutation of both CUP elements markedly activated transcription. Thus, it appears that dual CUP regulatory elements repress transcription of the C/EBPalpha gene prior to induction of the adipocyte differentiation program.

Transcriptional repression by human adenovirus E1A N terminus/conserved domain 1 polypeptides in vivo and in vitro in the absence of protein synthesis

The human adenovirus E1A 243R protein (243 residues) transcriptionally represses a set of cellular genes that regulate cellular growth and differentiation. We describe two lines of evidence that E1A repression does not require cellular protein synthesis but instead involves direct interaction with a cellular protein(s). First, E1A 243R protein represses an E1A-repressible promoter in the presence of inhibitors of protein synthesis, as shown by cell microinjection-in situ hybridization. Second, E1A 243R protein strongly represses transcription in vitro from promoters of the E1A-repressible genes, human collagenase, and rat insulin type II. Repression in vitro is promoter-specific, and an E1A polypeptide containing only the N-terminal 80 residues is sufficient for strong repression both in vivo and in vitro. By use of a series of E1A 1-80 deletion proteins, the E1A repression function was found to require two E1A sequence elements, one within the nonconserved E1A N terminus, and the second within a portion of conserved region 1 (40-80). These domains have been reported to possess binding sites for several cellular transcription regulators, including p300, Dr1, YY1, and the TBP subunit of TFIID. The in vitro transcription-repression system described here provides a powerful tool for the further analysis of molecular mechanism and the possible role of these cellular factors.