Evolution of the expression of the Gld gene in the reproductive tract of Drosophila.

During the preadult development of Drosophila melanogaster, the GLD (glucose dehydrogenase) gene (Gld) is expressed in a variety of tissues, including the immature reproductive tract. At the adult stage the expression of Gld becomes largely restricted to the reproductive tract of males and females. We examined the expression of GLD in the adult reproductive tract of 50 species in the genus Drosophila, as well as in those of a few representative species from four other closely related genera. GLD exhibits considerable organ-specific diversity in the reproductive tract of males and females. Among these species, five male GLD phenotypes and six female GLD phenotypes were found. In contrast, the preadult expression of GLD in representative species from each distinct adult pattern type was determined and found to be highly conserved in both the immature reproductive tract and non-reproductive organs. Moreover, the set of reproductive organs that express GLD during preadult development is equivalent to the sum of the five male and six female adult GLD phenotypes. To initially define the contribution of cis- versus trans-acting factors responsible for differences in adult GLD expression between two of these species--D. melanogaster and D. pseudoobscura--we transferred the D. pseudoobscura Gld to the genome of D. melanogaster and investigated its expression. GLD expression patterns of these transformants displayed characteristics that are unique to both species, suggesting the presence of both cis- and trans-acting differences between these two species.     

Molecular evolution and population genetic analysis of candidate female reproductive genes in Drosophila

Molecular analyses in several taxa have consistently shown that genes involved in reproduction are rapidly evolving and subjected to positive selection. The mechanism behind this evolution is not clear, but several proposed hypotheses involve the coevolution between males and females. In Drosophila, several male reproductive proteins (Acps) involved in male-male and male-female interactions show evidence of rapid adaptive evolution. What has been missing from the Drosophila literature is the identification and analysis of female reproductive genes. Recently, an evolutionary expressed sequence tag analysis of Drosophila female reproductive tract genes identified 169 candidate female reproductive genes. Many of these candidate genes still await further molecular analysis and independent verification of positive selection. Our goal was to expand our understanding of the molecular evolution of Drosophila female reproductive genes with a detailed polymorphism and divergence study on seven additional candidate female reproductive genes and a reanalysis of two genes from the above study. We demonstrate that 6 candidate female genes of the 9 genes surveyed show evidence of positive selection using both polymorphism and divergence data. One of these proteins (CG17012) is modeled to reveal that the sites under selection fall around and within the active site of this protease, suggesting potential differences between species. We discuss our results in light of potential function as well as interaction with male reproductive proteins.     

Meta-analysis of sex differences in gene expression in schizophrenia

Schizophrenia is a severe psychiatric disorder which influences around 1 % of the worldwide population. Differences between male and female patients with schizophrenia have been noted. There is an earlier age of onset in males compared with females with this diagnosis, and in addition, there are differences in symptom profiles between the sexes. The underlying molecular mechanism of sex difference remains unclear. Here we present a comprehensive analysis to reveal the sex differences in gene expression in schizophrenia with stringent statistics criteria. We compiled a data set consisting of 89 male controls, 90 male schizophrenia patients, 35 female controls and 32 female schizophrenia patients from six independent studies of the prefrontal cortex (PFC) in postmortem brain. When we tested for a sex by diagnosis interaction on gene expression, 23 genes were up-regulated and 23 genes were down-regulated in the male group (q-value?<?0.05), several genes are related to energy metabolism, while 4 genes are located on sex chromosome. No genes were statistically significant in the female group when multiple testing correction were conducted (q-value <0.05), most likely due to the small sample size. Our protocol and results from the male group provide a starting point for identifying the underlying different mechanism between male and female schizophrenia patients.     

Sexual Dimorphism in the Expression of Mitochondria-Related Genes in Rat Heart at Different Ages

Cardiovascular disease (CVD) is the leading cause of mortality worldwide. Moreover, sex and age are considered major risk factors in the development of CVDs. Mitochondria are vital for normal cardiac function, and regulation of mitochondrial structure and function may impact susceptibility to CVD. To identify potential role of mitochondria in sex-related differences in susceptibility to CVD, we analyzed the basal expression levels of mitochondria-related genes in the hearts of male and female rats. Whole genome expression profiling was performed in the hearts of young (8-week), adult (21-week), and old (78-week) male and female Fischer 344 rats and the expression of 670 unique genes related to various mitochondrial functions was analyzed. A significant (p<0.05) sexual dimorphism in expression levels of 46, 114, and 41 genes was observed in young, adult and old rats, respectively. Gene Ontology analysis revealed the influence of sex on various biological pathways related to cardiac energy metabolism at different ages. The expression of genes involved in fatty acid metabolism was significantly different between the sexes in young and adult rat hearts. Adult male rats also showed higher expression of genes associated with the pyruvate dehydrogenase complex compared to females. In young and adult hearts, sexual dimorphism was not noted in genes encoding oxidative phosphorylation. In old rats, however, a majority of genes involved in oxidative phosphorylation had higher expression in females compared to males. Such basal differences between the sexes in cardiac expression of genes associated with energy metabolism may indicate a likely involvement of mitochondria in susceptibility to CVDs. In addition, female rats showed lower expression levels of apoptotic genes in hearts compared to males at all ages, which may have implications for better preservation of cardiac mass in females than in males.     

Juvenile hormone regulation of male accessory gland activity in the red flour beetle, Tribolium castaneum

Male accessory gland proteins (Acps) act as key modulators of reproductive success in insects by influencing the female reproductive physiology and behavior. We used custom microarrays and identified 112 genes that were highly expressed in male accessory glands (MAG) in the red flour beetle, Tribolium castaneum. Out of these 112 identified genes, 59 of them contained sequences coding for signal peptide and cleavage site and the remaining 53 contained transmembrane domains. The expression of 14 of these genes in the MAG but not in other tissues of male or female was confirmed by quantitative real-time PCR. In virgin males, juvenile hormone (JH) levels increased from second day post adult emergence (PAE), remained high on third day PAE and declined on fourth day PAE. The ecdysteroid titers were high soon after adult emergence but declined to minimal levels from 1 to 5 days PAE. Feeding of juvenile hormone analog, hydroprene, but not the ecdysteroid analog, RH-2485, showed an increase in size of MAGs, as well as an increase in total RNA and protein content of MAG. Hydroprene treatment also increased the expression of Acp genes in the MAG. RNAi-mediated knock-down in the expression of JHAMT gene decreased the size of MAGs and expression of Acps. JH deficiency influenced male reproductive fitness as evidenced by a less vigor in mating behavior, poor sperm transfer, low egg and the progeny production by females mated with the JH deficient males. These data suggest a critical role for JH in the regulation of male reproduction especially through MAG secretions.     

Vitellogenesis in Anolis pulchellus: induction of VTG-like protein in liver explants from male and immature lizards.

Vitellogenin (VTG) synthesis has been described as an ideal system to study the hormonal regulation of gene expression. In Xenopus the molecular aspects of this control have been analyzed; however, in other non-mammalian species such as reptiles, very few studies approaching this level have been undertaken. We report on the induction by estradiol-17 beta of VTG-like proteins in liver explants from adult males and immature male and female lizards (A. pulchellus). A concentration of 10(-7) M was optimum for adult males while a higher concentration (10(-6) M) is required for the immature animals. No differences were observed in the hormonal induction in male and female immature animals, suggesting that there are no sexual distinctions in the liver at this stage. The effect of the hormone in male liver appears to be primarily on mRNA synthesis, since increases in 3H-uridine incorporation in total RNA were prevented by addition of 1 microgram/ml of the RNA polymerase II inhibitor alpha-Amanitin; however, rRNA synthesis was also increased as observed by agarose gel analysis. A 48 hr lag period was required for the detection of the intracellular as well as the secreted VTG-like protein. Electrophoretical analysis of the secretory products revealed the induction of a group of phosphoproteins immunologically related to yolk lipovitellin whose molecular weights range from 116,000 to 200,000.     

金钱鱼下丘脑转录组分析及其对雌激素在体注射的响应

为探究XX雌性和XY雄性金钱鱼(Scatophagus argus)下丘脑中的差异表达基因及雌激素(17β-Estradiol,E2)在体注射对XY雄鱼下丘脑中基因表达的影响,开展了转录组测序分析,包括测序数据质控、基因功能注释,差异基因筛选、鉴定和差异基因功能富集分析等,并利用实时定量PCR(Real-time quantitative PCR, qPCR)检测了金钱鱼下丘脑中相关基因的表达。金钱鱼下丘脑转录组共测得Clean reads 275833710,测序质量30(Q30)大于95%, GC含量值大于48%。其中, Ctrl-XX-H vs. Ctrl-XY-H组,共筛选和鉴定了91个差异表达基因,包括36个上调基因和55个下调基因。在Ctrl-XY-H vs. E2-XY-H组,筛选和鉴定了28个差异表达基因,包括11个上调基因和17个下调基因。GO和KEGG富集分析发现,差异表达基因主要显著富集在细胞、单生物过程,膜、膜组分,结合等生物学功能及泛醌和其他萜类-醌生物合成及类固醇激素生物合成通路等。转录组和qPCR结果表明, XX和XY金钱鱼下丘脑中prl、ccna1和hs...     

Methylation changes in muscle and liver tissues of male and female mice exposed to acute and chronic low-dose X-ray-irradiation

The biological and genetic effects of chronic low-dose radiation (LDR) exposure and its relationship to carcinogenesis have received a lot of attention in the recent years. For example, radiation-induced genome instability, which is thought to be a precursor of tumorogenesis, was shown to have a transgenerational nature. This indicates a possible involvement of epigenetic mechanisms in LDR-induced genome instability. Genomic DNA methylation is one of the most important epigenetic mechanisms. Existing data on radiation effects on DNA methylation patterns is limited, and no one has specifically studied the effects of the LDR. We report the first study of the effects of whole-body LDR exposure on global genome methylation in muscle and liver tissues of male and female mice. In parallel, we evaluated changes in promoter methylation and expression of the tumor suppressor gene p16(INKa) and DNA repair gene O(6)-methylguanine-DNA methyltransferase (MGMT). We observed different patterns of radiation-induced global genome DNA methylation in the liver and muscle of exposed males and females. We also found sex and tissue-specific differences in p16(INKa) promoter methylation upon LDR exposure. In male liver tissue, p16(INKa) promoter methylation was more pronounced than in female tissue. In contrast, no significant radiation-induced changes in p16(INKa) promoter methylation were noted in the muscle tissue of exposed males and females. Radiation also did not significantly affect methylation status of MGMT promoter. We also observed substantial sex differences in acute and chronic radiation-induced expression of p16(INKa) and MGMT genes. Another important outcome of our study was the fact that chronic low-dose radiation exposure proved to be a more potent inducer of epigenetic effects than the acute exposure. This supports previous findings that chronic exposure leads to greater genome destabilization than acute exposure.     

A genomic analysis of Drosophila somatic sexual differentiation and its regulation

In virtually all animals, males and females are morphologically, physiologically and behaviorally distinct. Using cDNA microarrays representing one-third of Drosophila genes to identify genes expressed sex-differentially in somatic tissues, we performed an expression analysis on adult males and females that: (1) were wild type; (2) lacked a germline; or (3) were mutant for sex-determination regulatory genes. Statistical analysis identified 63 genes sex-differentially expressed in the soma, 20 of which have been confirmed by RNA blots thus far. In situ hybridization experiments with 11 of these genes showed they were sex-differentially expressed only in internal genital organs. The nature of the products these genes encode provides insight into the molecular physiology of these reproductive tissues. Analysis of the regulation of these genes revealed that their adult expression patterns are specified by the sex hierarchy during development, and that doublesex probably functions in diverse ways to set their activities.