Subcellular location and expression pattern of autoimmune regulator (Aire), the mouse orthologue for human gene defective in autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED).

Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), also known as autoimmune polyglandular syndrome Type I (APS1), is an autosomal recessive autoimmune disease caused by mutations in a gene designated as AIRE (autoimmune regulator). Here we have studied the expression of Aire in transfected cell lines and in adult mouse tissues. Our results show that Aire has a dual subcellular location and that it is expressed in multiple immunologically relevant tissues such as the thymus, spleen, lymph nodes, and bone marrow. In addition, Aire expression was detected in various other tissues such as kidney, testis, adrenal glands, liver, and ovary. These findings suggest that APECED protein might also have a function(s) outside the immune system.(J Histochem Cytochem 49:197-208, 2001)     

A specific anti-Aire antibody reveals aire expression is restricted to medullary thymic epithelial cells and not expressed in periphery

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy is an autoimmune disorder caused by mutations in the autoimmune regulator gene AIRE. We examined the expression of Aire in different organs (thymus, spleen, and lymph nodes) in C57BL/6 mice, using a novel rat mAb, specific for murine Aire. Using flow cytometry, directly fluorochrome-labeled mAb revealed Aire expression in a rare thymic cellular subset that was CD45(-), expressed low levels of Ly51, and was high for MHC-II and EpCam. This subset also expressed a specific pattern of costimulatory molecules, including CD40, CD80, and PD-L1. Immunohistochemical analysis revealed that Aire(+) cells were specifically localized to the thymus or, more precisely, to the cortico-medulla junction and medulla, correlating with the site of negative selection. Although in agreement with previous studies, low levels of Aire mRNA was detected in all dendritic cell subtypes however lacZ staining, immunohistochemistry and flow cytometry failed to detect Aire protein. At a cellular level, Aire was expressed in perinuclear speckles within the nucleus. This report provides the first detailed analysis of Aire protein expression, highlighting the precise location at both the tissue and cellular level.     

Cell cycle regulators in bladder cancer: relationship to schistosomiasis

Dysregulation of cell cycle control may lead to genomic instability, neoplastic transformation and tumor progression. In terms of the particular roles in regulation of the cell-cycle, p21(WAF1) causes growth arrest through inhibition of cyclin-dependant kinases required for G1/S transition. P16 (INK4A) and p15 (INK4B) are thought to act as tumor suppressors, since their inactivation and/or deletion are observable in various types of malignancies. Cyclin D1 is hypothesized to control cell cycle progression through the G1-S check point. The present study evaluated p21 expression, p16 and p15 gene deletion and cylin D1 expression in bladder carcinoma among Egyptian patients, in relation to different clinicopathological features of the tumors and presence or absence of bilharziasis. Tissue specimens were obtained from 132 patients with bladder carcinoma and 50 normal tissue samples from the same patients served as control. P21 was determined by Western blot (WB) and enzyme immunoassay (EIA), p16 and p15 gene deletions were examined by polymerase chain reaction (PCR) and Cyclin D1 was detected by WB. Levels of p21 were lower in malignant tumors than in normal tissues. Lower expression of p21 was evident in lymph node positive, well differentiated tumors and squamous cell carcinoma (SCC) than in lymph node negative, poorly differentiated tumors and transitional cell carcinoma (TCC). In all normal samples, p15 and p16 genes were detected while cyclin D1 was not detected. P16 and p15 genes were deleted in 38.7% (41/106) and 30.2% (32/106) of bladder tumors respectively. The deletion of both genes was associated with poor differentiation grade and presence of bilharziasis. P16 deletion was also correlated to advancing tumor stage. Cyclin D1 was expressed in 57.5% of bladder tumors (69/120), where its expression was correlated to early stage, well differentiation grade, schistomiasis, and low levels of p21. Cell cycle is dysregulated in bladder carcinoma. This was evident from the increased expression of cyclin D1, the decreased levels of p21 and the deletion of p15 and p16 genes. Moreover, p16 and p15 gene deletion was related to tumor progression and might have a role in bilharzial bladder carcinogenesis. Cyclin D1 over-expression appears to be an early event in bladder cancer and might explain bilharzial associated bladder carcinogenesis.     

家蚕miR-2769靶基因的鉴定及表达分析

【目的】MiRNAs在昆虫变态发育过程中发挥非常重要的作用。对家蚕Bombyx mori miRNAs及靶基因的研究将有助于阐明miRNAs参与调控家蚕变态发育的分子机制。【方法】往家蚕5龄第2天幼虫血淋巴注射蜕皮激素20E后,qRT-PCR检测miR-2769在家蚕脂肪体中的表达;通过生物信息学方法预测家蚕miR-2769的靶基因;利用双荧光酶报告载体系统分析miR-2769与预测靶基因BmE75B的互作;qRT-PCR检测miR-2769及其靶基因BmE75不同剪接体在家蚕不同发育时期(幼虫、蛹和成虫)和幼虫不同组织(头、表皮、丝腺、脂肪体、精巢、卵巢、马氏管、中肠和血淋巴)中的表达量。【结果】研究结果表明,miR-2769可通过与家蚕BmE75B的3′UTR区结合位点的互作,显著抑制荧光素酶报告基因的表达。qRT-PCR结果表明,miR-2769和BmE75A/BmE75B在20E诱导家蚕脂肪体中表达趋势相反。时空表达分析结果表明,miR-2769与BmE75的不同剪接体在家蚕不同发育时期和不同组织中均具有特异性表达特征。在家蚕变态发育的不同阶段,miR-2769和BmE75A的表达量均较低,而BmE75B在蛹期表达量较高,BmE75C在5龄末幼虫和蛹早期有极高表达水平。此外,miR-2769与BmE75不同剪接体均存在一定程度的表达负相关。在家蚕5龄幼虫血淋巴中miR-2769可促进BmE75A的表达,在脂肪体中miR-2769可促进BmE75B的表达,而在其他组织中miR-2769抑制BmE75不同剪接体的表达。【结论】家蚕miR-2769可通过与BmE75B的3′UTR区的互作对BmE75不同剪接体的表达进行负调控。     

Isolation and initial characterization of a novel zinc finger gene, DNMT3L, on 21q22.3, related to the cytosine-5-methyltransferase 3 gene family

We have isolated the DNMT3L gene that is related to the cytosine-5-methyltransferase 3 (DNMT3) family. The gene is located on chromosome 21q22.3 between the AIRE and the KIAA0653 genes and spans approximately 16 kb of genomic sequence. The encoded protein of 387 amino acids has a cysteine-rich region containing a novel-type zinc finger domain that is conserved in DNMT3A and DNMT3B but also in ATRX, a member of the SNF2 protein family. The novel domain, called an ADD (ATRX, DNMT3, DNMT3L)-type zinc finger, contains two subparts: a C2C2 and an imperfect PHD zinc finger. Expression of the DNMT3L mRNA was not detectable by Northern blotting; however, RT-PCR amplification revealed that it is expressed at low levels in several tissues including testis, ovary, and thymus.     

Partial cloning and expression of the cyclin B gene in the ovary of the bullseye puffer (Sphoeroides annulatus)

The bullseye puffer is a marine fish species with great potential for aquaculture in Mexico, and the understanding of its reproductive physiology at every level of biological organization is essential in order to succeed. Several molecules orchestrate the complex process of oocyte maturation and spawning. One of these molecules is cyclin B, which is the regulatory subunit of the maturation-promoting factor. In this study, a fragment of the cyclin B gene was isolated from the ovary of the bullseye puffer using an RT-PCR approach. The gene fragment was homologous to the cyclin B2 gene of other vertebrate species. Similar levels of cyclin B gene expression were detected in ovaries at different developmental stages, except for atretic ovaries from captive fish which did not spawn. However, cyclin B gene expression was maintained in captive fish treated with LHRH-a to induce spawning, and appeared to be similar to the pattern observed in wild fish. It is possible that the reduced expression of cyclin B in atretic ovaries is the result of mRNA degradation during atresia. Alternatively, reduced gene expression could be a controlling factor in the process of oocyte reabsorption since cyclin B is required for final oocyte maturation and ovulation.     

Enhancement of lymphocyte responsiveness by a gain-of-function mutation of ZAP-70.

The protein tyrosine kinase ZAP-70 plays an essential role in T-cell activation and development. After T-cell receptor stimulation, ZAP-70 is associated with the receptor and is phosphorylated on many tyrosine residues, including tyrosine 292 (Y-292), in the region between the C-terminal SH2 domain and the kinase domain (interdomain B). Here we show that a mutation of Y-292 (292F) or deletion of interdomain B enhanced the ability of ZAP-70 to reconstitute B-cell receptor stimulation-dependent NF-AT induction in a B-cell line deficient in Syk. In contrast, in a T-cell line, expression of 292F led to basal NF-AT induction independent of T-cell receptor stimulation. These results demonstrate that the role of Y-292 is to negatively regulate the function of ZAP-70 in lymphocytes. This appears to be a dominant function of interdomain B because deletion of most of interdomain B also resulted in a mutant of ZAP-70 with enhanced ability to reconstitute Syk-deficient DT-40 B cells. Since our biochemical studies did not reveal an effect of the 292F mutation on either the kinase activity of ZAP-70 or on the ability of ZAP-70 to bind to the receptor, we propose a model in which Y-292 interacts with an inhibitory protein to negatively regulate ZAP-70 function.