The regulation of <Emphasis Type="Italic">yp3</Emphasis> expression in the <Emphasis Type="Italic">Drosophila melanogaster</Emphasis> fat body

The regulation of the Drosophila melanogaster yolk protein genes 1 and 2 have been well characterised. Cis-acting DNA elements and trans-acting factors regulating ovarian fat body and sex-specific expression have been identified. In this paper we have analysed the regulation of yolk protein 3, which is separated from the other two genes on the X-chromosome. We have separated sex-specific control from fat body control in some constructs in transgenic flies. We propose that the organisation of the regulatory elements in yp3 differs from yp1 and yp2 for control of fat body expression and that it closely resembles the regulation of a reporter gene using Musca and Calliphora yp promoter enhancer sequences in transgenic Drosophila.     

Organization and expression of mouse Hox3 cluster genes

Summary The three yolk protein genes (yp) of Drosophila melanogaster are transcribed in a sex- and tissue-limited fashion. We have searched for cis-regulatory sequences in regions flanking yp1 and yp2 to identify the elements that confer female-specific expression in the fat body. One such 127 by element has previously been identified in this region. We show here the existence of two additional regions which confer female fat body-specific expression on an Adh reporter gene and on the native yp2 gene, respectively. This suggests some redundancy in the regulation of expression of the yp genes. Computer searches for putative binding sites for the DSX protein, which regulates sex-specific expression of the yp genes, revealed several such sites in our constructs. However, the significance of these is unclear since many such sites also occur in genes which one would not expect to be regulated in a sex-specific manner (e.g. Adh, Actin 5C). We suggest that DSX acts in concert with other proteins to mediate sex- and tissue-specific expression of the yp genes.     

Conservation and divergence in the control of yolk protein genes in dipteran insects

 We have investigated the conservation of regulatory elements for sex- and tissue-specific gene expression in three dipteran species, Drosophila melanogaster, Musca domestica and Calliphora erythrocephala, using the yolk protein (yp) genes. Yolk proteins of the fruitfly, medfly, housefly and blowfly are very well conserved both in their sequence and their expression in ovarian follicle cells and in fat bodies of adult females. Furthermore, yp regulation by both hormonal and nutritional factors shows similar features in all four species. To study conservation of yp regulation in dipteran insects, we tested 5′ flanking regions from one Musca yp gene and one Calliphora yp gene for enhancer functions in D. melanogaster. Two fragments of 823 and 1046 bp isolated from Musca and Calliphora yp genes, respectively, are able to direct correct expression of a reporter gene in the ovarian follicle cells of transformed Drosophila at specific stages during oogenesis. Surprisingly, these enhancers do not confer sex-specific reporter gene expression in the fat body, as expression was found in both sexes of the transformed flies. None-the-less by in vitro DNA/protein interaction assays, a 284-bp DNA region from the Musca yp enhancer was able to bind the Drosophila DOUBLESEX (DSX) protein, which in D.melanogaster confers sex-specific expression of yp. We speculate that the sex-determining pathway is not directly involved in yp regulation in Musca or Calliphora adult females, but depends instead on hormonal controls to achieve sex-specific expression of yp genes in the adult. Received: 17 April 1997 / Accepted: 12 July 1997     

The nucleotide sequence of the gene coding for Drosophila melanogaster yolk protein 3

The entire sequence of the Drosophila melanogaster yolk protein 3 (YP3) gene (yp3), including 1822 nucleotides (nt) of 5'- and 834 nt of 3'-flanking DNA, has been determined. In addition, the 5' and 3' ends of the mRNA and the two introns have been mapped. The predicted amino acid sequence of YP3 has considerable homology (43%) to the other two yolk proteins of D. melanogaster. The nucleotide sequence of yp3 was compared to the other two yolk protein genes which have the same developmental pattern of expression. In addition to extensive homology between the protein coding regions, we found two small regions of homology between yp3 flanking sequences and a segment of DNA required for normal expression of the yolk protein 1 gene in adult female fat bodies.     

A tissue-specific transcription enhancer from the Drosophila yolk protein 1 gene

The yolk protein 1 gene (yp1) of Drosophila melanogaster is expressed only in the ovarian follicle cells and the fat bodies of adult females. We have previously shown that a different cis-acting DNA region is required for each of these tissue specificities. In this paper we use germ line transformation to localize and characterized one of these tissue-specific regulatory regions. We demonstrate that a 125 bp segment of DNA located 196 bp upstream of the yp1 cap site is sufficient to determine the sex-, stage-, and fat body-specific expression of the yp1 gene. We also find that this region can confer yp1-specific expression on a heterologous Drosophila promoter. This specificity is retained when the region is in different orientations and at different distances from the heterologous promoter. Thus a small regulatory region acts in vivo as a positive enhancer to determine the fat body expression pattern of yp1.     

Separate DNA sequences are required for normal female and ecdysone-induced male expression of Drosophila melanogaster yolk protein 1

Summary Drosophila melanogaster flies were transformed with a yp1-Adh fusion gene with 890 bp of yp1 5 flanking sequence. In an Adh ^- background these flies show a stage, tissue and sex-specific pattern of alcohol dehydrogenase (ADH) activity characteristic of yolk protein genes. ADH activity is not present in dsx ^D/dsx pseudomales indicating that this fragment contains sites where the dsx gene product exerts its effect. Transformed male flies do not exhibit ADH activity when injected with 20-hydroxyecdysone while synthesis of native yolk proteins is induced. Thus the hormone inducibility and sex regulation have been separated in this construct.     

Ash2l-1调控小鼠卵黄囊早期造血

作为甲基转移酶MLL/SET1复合体的核心成分之一,ASH2L能够促进组蛋白H3K4me3修饰的形成,并在小鼠早期胚胎发育过程中行使重要功能.在小鼠中,由于启动子的选择性使用,Ash2l会转录成两种不同长度的转录本并形成两种蛋白质亚型:ASH2L-1和ASH2L-2.目前有关该基因在小鼠胚胎发育中的作用机制及不同亚型的功能还不清楚.本文利用CRISPR/Cas9技术特异敲除Ash2l-1并研究该亚型的生理学功能.研究结果发现,当Ash2l-1缺失时,小鼠胚胎在E9.5~E10.5时发生致死.特别是Ash2l-1-/-E9.5胚胎的卵黄囊血管和早期造血发育存在明显缺陷.转录组测序结果显示,Ash2l-1的缺失影响红细胞发育和成熟、血管发生和形成相关基因的表达.H3K4me3的CUT&RUN结果显示,在一些表达下调关键基因的启动子区,H3K4me3修饰水平出现下降.以上结果表明,Ash2l-1在小鼠卵黄囊的早期造血和血管形成过程中是必不可少的,它可能是通过调控关键基因启动子区的H3K4me3修饰水平而控制这些基因的表达,从而在相关过程中行使功能.     

Characterization of a rice pollen-specific gene and its expression

Pollen development requires a large number of genes expressed in both sporophytic and gametophytic tissues. We have isolated a pollen-specific gene, PS1, from rice. PS1 is a unique gene in the rice genome and encodes a 164 amino acid long protein. RNA blot analysis shows that PS1 mRNAs accumulate specifically in rice anthers. When introduced into rice tissues by microprojectile bombardment, the PS1 promoter drives expression of a marker gene, β-glucuronidase, specifically in rice pollen. The PS1 gene and the deduced amino acid sequence of the PS1 protein share significant levels of homology with another monocot pollen-specific gene—the maize Zm-13 gene and its deduced protein, respectively. PS1 also shows some homology with the dicot tomato anther-specific gene LAT-52. Interestingly, the structure of the PS1 gene is more similar to that of the LAT-52 gene than to Zm-13. The coding regions of both PS1 and LAT-52 are interrupted by a single intron, and the positions of the introns are conserved in these genes. Moreover, there is considerable sequence homology in the introns of the PS1 and LAT-52 genes in regions immediately upstream of the 3' splice sites. The upstream regulatory sequences of the PS1 gene show several regions of homology with other pollen- or anther-specific genes from a number of plant species. The conservation of coding sequences of PS1 from rice, Zm-I3 from maize, and LAT-52 from tomato suggests a functional conservation of their gene products. Similarities in the regulatory regions of PS1 and other anther- or pollen-specific genes among monocotyledonous and dicotyledonous species indicate that at least some regulatory features controlling gene expression in male reproductive tissues are conserved. This is supported by the preservation of pollen-specific expression from the rice PS1 promoter when it is introduced into tobacco plants by Agrobacterium Ti plasmid-mediated transformation.     

Identification and comparisons of the yolk polypeptides and the genes which code for them in D. melanogaster sibling species

Summary The yolk proteins stored in Drosophila, oocytes for utilisation during embryogenesis are an ideal system for studying the regulation of gene expression during development. The 3 major polypeptides found in yolk in D. melanogaster are synthesised in the fat body and ovarian follicle cells and selectively accumulated by the oocyte during vitellogenesis. In order to understand more about their regulation and the mechanism of uptake, studies on other species are necessary.Three yolk polypeptides have previously been identified in the D. melanogaster sibling species (D. melanogaster, D. simulans, D. mauritiana, D. erecta, D. teissieri, D. orena and D. yakuba). In D. melanogaster three genes located on the X chromosome are known to code for these yolk polypeptides. in this study genomic Southern transfers and in situ hybridisation experiments were carried out on the sibling species. Using the three cloned yolk protein genes from D. melanogaster, homologous sequences could be detected in the sibling species. It is suggested that three yolk protein genes occur in each of these species, all being located on the X chromosome, and that two of the genes are very closely linked in these same species. Yolk protein gene-homologous DNA sequences have also been identified in two more distantly related species D. funebris and D. virilis.     

Diurnal rhythm in expression and release of yolk protein in the testis of Spodoptera littoralis (Lepidoptera: Noctuidae)

Circadian clocks (oscillators) regulate multiple life functions in insects. The circadian system located in the male reproductive tract of Lepidoptera is one of the best characterized peripheral oscillators in insects. Our previous research on the cotton leafworm, Spodoptera littoralis, demonstrated that this oscillator controls the rhythm of sperm release from the testis and coordinates sperm maturation in the upper vas deferens (UVD). We demonstrated previously that a protein that functions as yolk protein in females is also produced in cyst cells surrounding sperm bundles in the testis, and is released into the UVD. Here, we investigated the temporal expression of the yolk protein 2 (yp2) gene at the mRNA and protein level in the testis of S. littoralis, and inquired whether their expression is regulated by PER-based molecular oscillator. We describe a circadian rhythm of YP2 accumulation in the UVD seminal fluid, where this protein interacts with sperm in a circadian fashion. However, we also demonstrate that yp2 mRNA and YP2 protein levels within cyst cells show only a diurnal rhythm in light/dark (LD) cycles. These rhythms do not persist in constant darkness (DD), suggesting that they are non-circadian. Interestingly, the per gene mRNA and protein levels in cyst cells are rhythmic in LD but not in DD. Nevertheless, per appears to be involved in the diurnal timing of YP2 protein accumulation in cyst cells.     

A novel pleckstrin homology-related gene family defined by Ipl/Tssc3, TDAG51, and Tih1: tissue-specific expression, chromosomal location, and parental imprinting

We previously described a gene, Ipl (Tssc3), that is expressed selectively from the maternal allele in placenta, yolk sac, and fetal liver and that maps within the imprinted domain of mouse distal Chromosome (Chr) 7/human Chr 11p15.5 (Hum Mol Genet 6, 2021, 1997). Ipl is similar to TDAG51, a gene that is involved in FAS/CD95 expression. Here we describe another gene, Tih1 (TDAG/Ipl homologue 1), with equivalent sequence similarity to Ipl. Structural prediction indicates that the products of these three genes share a central motif resembling a pleckstrin-homology (PH) domain, and TIH1 protein has weak sequence similarity to the PH-domain protein SEC7/CYTOHESIN. Like Ipl, Tih1 is a small gene with a single small intron. Tih1 maps to distal mouse Chr 1 and human Chr 1q31, chromosomal regions that have not shown evidence for imprinting and, in contrast to Ipl, Tih1 is expressed equally from both parental alleles. Ipl, Tih1, and TDAG51 have overlapping but distinct patterns of expression. Tih1 and TDAG51 are expressed in multiple fetal and adult tissues. In contrast, during early mouse development Ipl mRNA and protein are highly specific for two tissues involved in maternal/fetal exchange: visceral endoderm of the yolk sac and labyrinthine trophoblast of the placenta. These findings highlight the dominance of chromosomal context over gene structure in some examples of parental imprinting and extend previous evidence for placenta-specific expression of imprinted genes. The data also define a new subfamily of PH domain genes. Received: 10 June 1999 / Accepted: 26 July 1999     

Opossum carboxylesterases: sequences,phylogeny and evidence for <Emphasis Type="Italic">CES</Emphasis> gene duplication events predating the marsupial-eutherian common ancestor

Background  

Carboxylesterases (CES) perform diverse metabolic roles in mammalian organisms in the detoxification of a broad range of drugs and xenobiotics and may also serve in specific roles in lipid, cholesterol, pheromone and lung surfactant metabolism. Five CES families have been reported in mammals with human CES1 and CES2 the most extensively studied. Here we describe the genetics, expression and phylogeny of CES isozymes in the opossum and report on the sequences and locations of CES1, CES2 and CES6 'like' genes within two gene clusters on chromosome one. We also discuss the likely sequence of gene duplication events generating multiple CES genes during vertebrate evolution.