前列腺素在胚胎着床和蜕膜化中的作用

前列腺素在哺乳动物的雌性生殖过程中起着十分重要的作用.环氧合酶-2 (cyclooxygenase-2, COX-2)主要在子宫着床位点处胚胎周围的基质细胞中表达, 介导着床和蜕膜化过程.由COX-2和微粒体型前列腺素E合成酶-1途径来源的前列腺素E 2 (prostaglandin E2, PGE2)在胚胎着床和蜕膜化过程中起重要作用.子宫中产生的前列腺素I 2 (prostaglandin I2, PGI2)通过核受体过氧化物酶体增殖因子活化受体δ(peroxisome proliferator-activated receptorδ,PPARδ)在胚胎着床过程中起关键作用.质膜上的前列腺素转运蛋白(prostaglandin transporter, PGT)通过转运新合成的前列腺素, 来满足胚胎着床和蜕膜化过程中对前列腺素的需求, 并维持前列腺素的代谢平衡.     

小鼠子宫蜕膜化过程中细胞周期调控相关因子的研究进展

多倍性细胞的产生作为小鼠子宫蜕膜化的标志之一,其过程是受到细胞周期调控因子的严格调控的。目前对于细胞周期调控因子在蜕膜过程的研究已经很多,但有一些分子机制尚不明确,该文对近几年来小鼠子宫蜕膜化过程中细胞周期调控因子以及这些因子相互作用的研究做出综述,以期对未来临床医学提供更多理论依据。     

Genome-Wide Analyses of Gene Expression during Mouse Endochondral Ossification

Background

Endochondral ossification is a complex process involving a series of events that are initiated by the establishment of a chondrogenic template and culminate in its replacement through the coordinated activity of osteoblasts, osteoclasts and endothelial cells. Comprehensive analyses of in vivo gene expression profiles during these processes are essential to obtain a complete understanding of the regulatory mechanisms involved.

Methodology/Principal Findings

To address these issues, we completed a microarray screen of three zones derived from manually segmented embryonic mouse tibiae. Classification of genes differentially expressed between each respective zone, functional categorization as well as characterization of gene expression patterns, cytogenetic loci, signaling pathways and functional motifs both confirmed reported data and provided novel insights into endochondral ossification. Parallel comparisons of the microdissected tibiae data set with our previously completed micromass culture screen further corroborated the suitability of micromass cultures for modeling gene expression in chondrocyte development. The micromass culture system demonstrated striking similarities to the in vivo microdissected tibiae screen; however, the micromass system was unable to accurately distinguish gene expression differences in the hypertrophic and mineralized zones of the tibia.

Conclusions/Significance

These studies allow us to better understand gene expression patterns in the growth plate and endochondral bones and provide an important technical resource for comparison of gene expression in diseased or experimentally-manipulated cartilages. Ultimately, this work will help to define the genomic context in which genes are expressed in long bones and to understand physiological and pathological ossification.     

ADAM19 在小鼠睾丸发育中的时空表达

目的 阐明含有去整合素和金属蛋白酶结构域的跨膜蛋白19(ADAM19)在小鼠睾丸发育中的作用.方法 采用半定量RT-PCR和免疫组化两种实验方法,分别检测ADAM19 mRNA和蛋白质在小鼠睾丸发育中的时空表达.结果 ①最早在胚胎发育的15.5 d才能检测到ADAM19 mRNA的表达,后其表达随着胚胎发育天数的增加而逐渐升高,到围产期表达水平达到最高.出生后,ADAM19 mRNA的表达呈现显著下降的趋势,到成体睾丸中就几乎检测不到ADAM19的表达.②和其mRNA表达变化趋势一样,ADAM19蛋白也是首次在胚胎发育的15.5 d被检测到,一直持续存在到出生后一周,一周后则几乎检测不到;阳性表达信号主要定位在睾丸的曲细精管(睾索)中.结论 ADAM19 在小鼠睾丸中的表达具有显著的发育依赖性.     

Expression of Catenins during Mouse Embryonic Development and in Adult Tissues

Classical cadherins are cell-surface glycoproteins that mediate calcium-dependent cell adhesion. The cytoplasmic domain of these glycoproteins is linked to the cytoskeleton through the catenins (α, β and γ). The catenins are intracellular polypeptides that are part of a complex sub-membranous network modulating the adhesive ability of the cells. One approach to elucidate the role of these molecules in the cell is to investigate their distribution during mouse development and in adult tissues. This study reports that catenins are widely expressed but in varying amounts in embryos and adult tissues. The expression of all three catenins is most prominent in the adult heart muscle and in epithelia of all developmental stages. In other embryonic and adult tissues, lower expression of catenins was detected, e.g., in smooth muscle or connective tissue. Catenins are coexpressed with various cadherins in different tissues. Gastrulation is the first time during embryogenesis when a discrepancy occurs between the expression of catenins and E-cadherin. E-cadherin expression is suppressed in mesodermal cells but not the expression of catenins. This discrepancy suggests that another cadherin may interact with catenins. Similarly, E-cadherin is generally expressed in adult liver but not in the regions surrounding the central veins. In contrast, catenins are uniformly expressed in the liver, suggesting that they are associated with other cadherins in E-cadherin negative cells. Finally, the three catenins are not always concurrently expressed. For example, in peripheral nerves, only β-catenin is observable, and in smooth muscle plakoglobin is not detectable.     

小鼠早期胚胎发育过程中细胞凋亡及凋亡基因表达的检测

小鼠早期胚胎发育过程中凋亡现象大量存在,细胞凋亡与凋亡基因表达有关。应用彗星电泳法检测小鼠早期胚胎凋亡情况;应用巢式RT-PCR、免疫组化的方法检测了Bcl-2家族成员(Bax、Bcl-2、Bak、Bcl-xl)的表达变化情况。结果显示:随着胚胎细胞数目的增加,凋亡比率逐渐增大;Bax表达量在整个过程中基本不变,Bcl-2表达量逐渐上调,Bak、Bcl-xl的表达量逐渐降低。对小鼠早期胚胎发育过程中的基因表达研究对于揭示早期胚胎发育的机制有重大的意义。     

Analysis of Kif5b Expression during Mouse Kidney Development

Recent studies showed that kidney-specific inactivation of Kif3a produces kidney cysts and renal failure, suggesting that kinesin-mediated intracellular transportation is important for the establishement and maintenance of renal epithelial cell polarity and normal nephron functions. Kif5b, one of the most conserved kinesin heavy chain, is the mouse homologue of the human ubiquitous Kinesin Heavy Chain (uKHC). In order to elucidate the role of Kif5b in kidney development and function, it is essential to establish its expression profile within the organ. Therefore, in this study, we examined the expression pattern of Kif5b in mouse kidney. Kidneys from embryonic (E) 12.5-, 16.5-dpc (days post coitus) mouse fetuses, from postnatal (P) day 0, 10, 20 pups and from adult mice were collected. The distribution of Kif5b was analyzed by immunostaining. The possible involvement of Kif5b in kidney development was investigated in conditional mutant mice by using a Cre-LoxP strategy. This study showed that the distribution of Kif5b displayed spatiotemporal changes during postnatal kidney development. In kidneys of new born mice, Kif5b was strongly expressed in all developing tubules and in the ureteric bud, but not in the glomerulus or in other early-developing structures, such as the cap mesenchyme, the comma-shaped body, and the S-shaped body. In kidneys of postnatal day 20 or of older mice, however, Kif5b was localized selectively in the basolateral domain of epithelial cells of the thick ascending loop of Henle, as well as of the distal convoluted tubule, with little expression being observed in the proximal tubule or in the collecting duct. Conditional knock-down of Kif5b in mouse kidney did not result in detectable morphological defects, but it did lead to a decrease in cell proliferation rate and also to a mislocalization of Na⁺/K⁺/-ATPase, indicating that although Kif5b is non-essential for kidney morphogenesis, it is important for nephron maturation.     

The Tissue-Specific Gene Expression during Progression of Mouse Hepatocellular Carcinoma

Expression of hepato-specific genes in slow- and fast-growing hepatocellular murine carcinomas was studied. A fast-growing dedifferentiated transplantable hepatocarcinoma variant (fgHCC) arose from the highly differentiated slow-growing hepatocarcinoma (sgHCC). In contrast to the parental hepatocarcinoma, expression of the hepatocyte nuclear factor 4 (HNF4), one of the key regulators of hepatocyte differentiation, and several HNF-4-responsive genes, transferrin, transthyretin, hepatocyte nuclear factor 1 (HNF1), and serum albumin, was downregulated in fgHCC. The expression of exogenous HNF4 in the fgHCC cell culture partially restored the expression of hepato-specific genes and led to the formation of epithelial islets in the culture. The described system may serve as an appropriate model for further analysis of mechanisms underlying hepatocarcinogenesis and liver tumor progression.     

Complex Function and Expression of Delta during Drosophila Oogenesis

Delta (Dl) encodes a cell surface protein that mediates cell-cell interactions central to the specification of a variety of cell fates during embryonic and postembryonic development of Drosophila melanogaster. We find that the Delta protein is expressed intermittently in follicle cells and in germ-line cells during stages 1-10 of oogenesis. Furthermore, Delta expression during oogenesis can be correlated with a number of morphogenetic defects associated with sterility observed in Dl mutant females, including failure of stalk formation within the germarium and subsequent fusion of egg chambers, necrosis in germ-line cells, and multiphasic embryonic arrest of fertilized eggs. We have also identified a Dl mutation that leads to context-dependent defects in Dl function during oogenesis. Direct comparison of Delta protein expression with that of the Notch protein in the ovary reveals substantial, but incomplete, coincidence of expression patterns in space and time. We discuss possible roles for the Delta protein in cell-cell interactions required for cell fate specification processes during oogenesis in light of available developmental and histochemical data.     

Differential Expression of c-myc and N-myc during Oral Organogenesis of the Mouse Embryo

The expressions of the c- and N- myc proto-oncogenes during oral development of midgestational mouse embryos were examined by in situ hybridization in order to analyze their roles. In the mandibular rudiment, c- myc RNA was strongly expressed in the mesenchymal condensation around the ossification center in which high-level expression of 2 ar (osteopontin) was detected. In tooth germs, c- myc was strongly expressed in the epithelia at the bud stage, and its expression gradually became restricted to the inner enamel epithelia from the cap to bell stages. In contrast, N- myc expression was detected in the undifferentiated mesenchymal cells of the dental papilla. Incorporation of BrdU was examined immunohistochemically to study the relationship between the expressions of c- and N- myc and cell proliferation. Unexpectedly, the distribution of BrdU labelled regions was not coincident with the expressions of c- and N- myc . These results suggest that the level of myc expression is not necessarily related to cell proliferation.     

小鼠乳腺泌乳过程中葡萄糖转运载体mRNA的表达规律研究

实验采用荧光定量PCR方法研究了小鼠在妊娠和泌乳过程中葡萄糖转运载体SLC2A1、SLC2A4与SLC5A1 mRNA的表达规律.结果表明与妊娠期相比,SLC2A1在泌乳期的表达量上调,泌乳18 d是妊娠18 d表达量的11倍（P〈0.01）;SLC2A4的表达在妊娠和泌乳期无显著差异;SLCSA1的表达量从妊娠至泌乳期呈上升趋势,泌乳18 d是妊娠18 d表达量的2.5倍（P〈0.01）.SLC2A1是小鼠乳腺泌乳时主要的葡萄糖转运载体,SLCSA1在乳腺葡萄糖的转运过程中也发挥重要作用.