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PubMed1987

The human beta-globin gene contains a downstream developmental specific enhancer.

The human beta-globin gene is part of a multigene family and is expressed specifically in adult human erythroid tissue (for review, 1). When the human beta-globin is introduced into fertilized mouse eggs, it is first activated in foetal liver and remains expressed in adult erythroid tissues. It therefore mimicks the pattern of expression of its murine counterpart. It has previously been shown in tissue culture and transgenic mice that sequences downstream from the beta-globin promoter are involved in this regulation. We now show that at least part of these sequences are located 0.5-1.2kb downstream from the poly A addition site and constitute a transcriptional enhancer element that is erythroid and developmental specific.

Animals↗
PubMed2003

Transcript profiling coupled with spatial expression analyses reveals genes involved in distinct developmental stages of an arbuscular mycorrhizal symbiosis.

The formation of symbiotic associations with arbuscular mycorrhizal (AM) fungi is a phenomenon common to the majority of vascular flowering plants. Here, we used cDNA arrays to examine transcript profiles in Medicago truncatula roots during the development of an AM symbiosis with Glomus versiforme and during growth under differing phosphorus nutrient regimes. Three percent of the genes examined showed significant changes in transcript levels during the development of the symbiosis. Most genes showing increased transcript levels in mycorrhizal roots showed no changes in response to high phosphorus, suggesting that alterations in transcript levels during symbiosis were a consequence of the AM fungus rather than a secondary effect of improved phosphorus nutrition. Among the mycorrhiza-induced genes, two distinct temporal expression patterns were evident. Members of one group showed an increase in transcripts during the initial period of contact between the symbionts and a subsequent decrease as the symbiosis developed. Defense- and stress-response genes were a significant component of this group. Genes in the second group showed a sustained increase in transcript levels that correlated with the colonization of the root system. The latter group contained a significant proportion of new genes similar to components of signal transduction pathways, suggesting that novel signaling pathways are activated during the development of the symbiosis. Analysis of the spatial expression patterns of two mycorrhiza-induced genes revealed distinct expression patterns consistent with the hypothesis that gene expression in mycorrhizal roots is signaled by both cell-autonomous and cell-nonautonomous signals.

Expressed Sequence Tags↗
PubMed2006

MBD2 is a critical component of a methyl cytosine-binding protein complex isolated from primary erythroid cells.

The chicken embryonic beta-type globin gene, rho, is a member of a small group of vertebrate genes whose developmentally regulated expression is mediated by DNA methylation. Previously, we have shown that a methyl cytosine-binding complex binds to the methylated rho-globin gene in vitro. We have now chromatographically purified and characterized this complex from adult chicken primary erythroid cells. Four components of the MeCP1 transcriptional repression complex were identified: MBD2, RBAP48, HDAC2, and MTA1. These 4 proteins, as well as the zinc-finger protein p66 and the chromatin remodeling factor Mi2, were found to coelute by gel-filtration analysis and pull-down assays. We conclude that these 6 proteins are components of the MeCPC. In adult erythrocytes, significant enrichment for MBD2 is seen at the inactive rho-globin gene by chromatin immunoprecipitation assay, whereas no enrichment is observed at the active beta(A)-globin gene, demonstrating MBD2 binds to the methylated and transcriptionally silent rho-globin gene in vivo. Knock-down of MBD2 resulted in up-regulation of a methylated rho-gene construct in mouse erythroleukemic (MEL)-rho cells. These results represent the first purification of a MeCP1-like complex from a primary cell source and provide support for a role for MBD2 in developmental gene regulation.

Animals↗
PubMed2001

The Bradyrhizobium japonicum hsfA gene exhibits a unique developmental expression pattern in cowpea nodules.

The Bradyrhizobium japonicum host-specific fixation gene hsfA was identified as essential for nitrogen fixation on cowpea, but not required for nitrogen fixation on soybean or siratro. The DNA sequence of the hsfA promoter contains a consensus RpoN, -24/-12 binding site, suggesting the involvement of a regulatory protein that binds to an upstream activating sequence (UAS). To further explore the regulation of this interesting gene, serial deletions of the hsfA promoter were made and fused with the beta-glucuronidase (GUS) gene. The HsfA3 deletion, containing 60 bp 5' of the -24/-12 sequence, showed a similar level of GUS expression to that shown by the longest fusion construct (HsfA1), containing 464 bp of upstream sequence. In contrast, the HsfA4-GUS fusion, containing only 20 bp 5' of the -24/-12 region, showed no GUS activity, delimiting the location of a putative UAS to a 40-bp region. During nodule development, GUS expression first appeared in nodules 12 days postinoculation (dpi) and reached a maximum level of expression in approximately 17-day-old nodules. By 28 dpi, HsfA-GUS expression had returned to a low, basal level. These data were consistent with the detection of hsfA mRNA by in situ hybridization in 17-day-old nodules, but not in 28-day-old nodules. In contrast to the stage-specific expression in cowpea, HsfA-GUS expression increased with nodule development in HsfA3-inoculated soybean. These data indicate that HsfA expression is regulated in cowpea in a unique developmental manner and that the DNA regulatory regions that control this expression are confined to a short, promoter-proximal region.

Bacterial Proteins↗
PubMed1992

The p53 gene expression and its developmental regulation in schistosomes.

We have studied the gene expression, especially of the oncoproteins, and its regulation in schistosomes. Schistosomes have a complex life cycle with a defined dimorphic lifestyle. The parasite are so far unique in biology in expressing oncogene products in their adult stage. In order to characterize the expression and developmental regulation, a lambda gt 11 cDNA library and lambda EMBL4 genomic DNA library of each growth stage of Schistosoma mansoni and S. japonicum was constructed, and was screened with various monoclonal antibodies against oncogene products. One positive plaque reacted to anti-p53 antibody (Ab-2, Oncogene Science, Inc.) was further analyzed. This fusion protein was about 120 KDa in molecular weights, and expressed as 1.4 Kb RNA in the adult stage. P53 gene is well-known as the negative regulator of the cell cycle, and the mutations in the gene are turning out to be the most common genetic alterations in human cancers. The comparison of the gene structure among species and stages were being conducted. Chromosome structures, C-band formation, and the results of in situ hybridization using the phage probe would be discussed.

Animals↗
PubMed1993

Structure and expression of the nuclear gene coding for the chloroplast ribosomal protein L21: developmental regulation of a housekeeping gene by alternative promoters.

We have cloned and sequenced the nuclear gene of the chloroplast ribosomal protein L21 (rpl21) of Spinacia oleracea. The gene consists of five exons and four introns. All introns are located in the sequence which corresponds to the Escherichia coli-like central core of the protein. L21 mRNA is present in photosynthetic (leaves) and nonphotosynthetic (roots and seeds) plant organs, although large quantitative differences exist. Primer extension and S1 nuclease mapping experiments revealed the existence of two types of transcripts in leaves. The two corresponding start sites were defined as P1 and P2. In roots and seeds, we found only the shorter of the two transcripts (initiated at P2). The nucleotide sequence surrounding P2 resembles promoters for housekeeping and vertebrate r-protein genes. Analysis of several promoter constructions by transient expression confirmed that both transcripts originate from transcription initiation. Results are interpreted to mean that the expression of the rpl21 gene is regulated by alternative promoters. One of the promoters (P2) is constitutive, and the other one (P1) is specifically induced in leaves, i.e., its activation should be related to the transformation of amyloplasts or proplastids to chloroplasts. The gene thus represents the first example of a housekeeping gene which is regulated by the organ-specific usage of alternative promoters. Primer extension analysis and S1 nuclease mapping of another nucleus-encoded chloroplast ribosomal protein gene (rps1) give evidence that the same type of regulation by two-promoter usage might be a more general phenomenon of plant chloroplast-related ribosomal protein genes. Preliminary results indicate that presence of conserved sequences within the rpl21 and rps1 promoter regions which compete for the same DNA binding activities.

Amino Acid Sequence↗
PubMed2001

The mouse Na+-K+-ATPase gamma-subunit gene (Fxyd2) encodes three developmentally regulated transcripts.

The Na(+)-K(+)-ATPase is understood to function as a hetero-oligomer of alpha- and beta-subunits, but a third subunit, gamma, has been proposed to influence the enzyme's catalytic function. Recently, two variants of the gamma-subunit have been described in kidney, raising the possibility of multiple gamma-subunits with diverse functions. We now report the cloning and sequencing of the mouse gamma-subunit gene (Fxyd2). Analysis of the structure of the gene shows that it encodes three mRNAs that have distinct NH(2)-terminal (extracellular) encoding sequences but common transmembrane and COOH-terminal-encoding sequences resulting from differential splicing and, probably, alternate promoter usage. The three mRNAs have tissue-specific expression patterns. The existence of three different extracellular domains of the gamma-variants and how they may interact with the sodium pump to alter its cation transport properties must now be taken into account for future understanding of the modulation of the Na(+)-K(+)-ATPase by its gamma-subunit.

Alternative Splicing↗
PubMed1997

Developmental changes in ob gene expression and circulating leptin peptide concentrations.

We examined the developmental changes in murine white and brown adipose tissue leptin and circulating immunoreactive total leptin concentrations. The approximately 4.4 kb leptin mRNA levels were higher at 2 and 7d postnatal ages, but declined to adult levels by the 14d stage and remained so until 160d. Paralleling the mRNA concentrations, leptin peptide levels also were higher at 2d, 7d, and 14d, declining to adult values by the 21d weaning stage. No difference in mRNA levels was observed between brown-enriched and white adipose tissue. No sexual dimorphism was observed in the leptin mRNA or peptide levels between 14 and 160d; however, at 2 and 7d, while no sex related differences were observed in the peptide levels, adipose mRNA concentrations were mildly higher in males than in the females. We conclude that leptin mRNA and peptide levels are higher during consumption of a high fat milk diet. High levels of leptin with increasing food intake and body weight gain signify hypothalamic leptin receptor resistance during the immediate postnatal period.

Adipose Tissue↗
PubMed1997

Characterisation of a pea hsp70 gene which is both developmentally and stress-regulated.

A pea pod cDNA library was screened for sequences specific to lignifying tissue. A cDNA clone (pLP19) encoding the C-terminal region of a hsp70 heat shock protein hybridised only to pod mRNA from pea lines where pod lignification occurred. Expression of pLP19 was induced by heat shock in leaves, stems and roots of pea and chickpea plants. Four different poly(A) addition sites were observed in cDNAs derived from the same gene as pLP19. This gene was fully sequenced; unlike most hsp70 genes, it contains no introns. The 5'-flanking sequence contains heat shock elements and other potential regulatory sequences.

Amino Acid Sequence↗
PubMed2003

Epigenetic interactions between Arabidopsis transgenes: characterization in light of transgene integration sites.

The stochastic variability of expression that is a characteristic of eukaryotic nuclear transgenes is often attributed to epigenetic mechanisms that are triggered by repetitive transgene locus structures and influenced by chromosomal position effects. In order to address the contribution of chromosomal position effects in the context of a fully sequenced genome, a novel set of transgene loci was established in the compact genome of Arabidopsis thaliana. Transgenes expressing GFP-tagged or GUS-tagged fusion proteins of Arabidopsis COP1 collectively displayed three types of gene silencing, which are distinguished by their developmental timing, gene dosage dependence, (post)transcriptional control, and extent of endogene co-suppression. Subsequently, the heritability of epistatic interactions between allelic and non-allelic transgene loci was investigated in light of both intrinsic transgene features, in particular T-DNA copy number per locus, and chromosomal insertion sites. The notion that chromosomal flanking sequences underlie the ability of transgenes to function as masters or targets of epigenetically heritable trans-silencing interactions was generally not favored by our data. Moreover, among single T-DNA loci at different chromosomal locations the great majority showed homozygosity-dependent posttranscriptional silencing. However, spontaneous silencing (in cis) may be promoted by a pericentromeric location. Instead, intrinsic transgene features correlated with all major aspects of silencing behavior tested.

Arabidopsis↗
PubMed1986

Gene regulation and evolution in the chorion locus of Bombyx mori. Structural and developmental characterization of four eggshell genes and their flanking DNA regions.

We report on the detailed structural and developmental characterization of four chorion genes and a truncated pseudogene located within a 9.5 X 10(3) base chromosomal segment. These genes belong to the A and B multigene families and, like previously characterized moth chorion genes, are arranged in tightly linked pairs, which are divergently transcribed (A/B.L11 and A/B.L12). On the basis of their high degree of sequence divergence, the A genes define two distinct subfamilies, while the more homologous B genes represent different copies of the same gene type. The A.L11 and B.L11 introns are much longer, in each case because of a single inserted DNA segment that is missing from A.L12 or B.L12. The 2.1 X 10(3) base insertion in A.L11 is the first retrovirus-like transposable element characterized in Bombyx mori. The very short 5' flanking sequences of A/B.L11 and A/B.L12 (277 and 276 base-pairs) are distinct as shown by hybridization but both recur in additional chorion gene pairs, forming two respective classes that are expressed during distinctly different developmental periods. The divergently transcribed genes of each pair, which border the same 5' flanking sequence, are expressed co-ordinately, during the same developmental period. Detailed comparisons of the 5' flanking regions, and of the corresponding region of the Drosophila s15-1 chorion gene, revealed numerous, very short sequence elements that are shared. One such element, T-C-A-C-G-T, is also associated with all five sequenced Drosophila chorion genes. Some elements are repeated in a dyad symmetrical pattern, i.e. are associated with each of the two genes in a pair, while others, including T-C-A-C-G-T, occur only once per 5' flanking region, and, if functionally important, would presumably act bi-directionally on both genes of the pair.

Animals↗
PubMed1995

Expression of an amino acid biosynthesis gene in tomato flowers: developmental upregulation and MeJa response are parenchyma-specific and mutually compatible.

The gene coding for threonine deaminase (TD), the enzyme which catalyzes the first committed step in the biosynthesis of isoleucine, was isolated from tomato as a consequence of its unusual 500-fold upregulation in floral organs. It was subsequently shown that TD is induced in potato leaves in response to wounding, abscisic acid and methyl jasmonate (MeJa). Detailed analysis presented here, reveals an intricate developmental regulation pattern of gene expression in flowers that is operating solely in parenchyma territories. Yet, despite its high pre-existing expression level, TD in flowers can be further induced by MeJa. Induction of TD in flowers as well as in leaves is effective only in the parenchyma domains, irrespective of the prior expression levels. TD is neither expressed nor induced in epidermal, vascular or sporogenous tissues. Promoter analysis in transgenic tomato plants indicates that induction of TD follows identical kinetics in flowers and leaves. Furthermore, the 'conditioning' of developmental upregulation in flowers, the response to MeJa in flowers and leaves, and the parenchyma-specific expression are all mediated by the cis-elements within the proximal 192 bp of the promoter. Promoter elements regulating the correct organ-specific expression are located, however, further upstream. The promoter constructs used in this study can serve as useful tools for expressing extremely high levels of transgenes in specific cells. A scheme explaining tissue-specific response to MeJa, in conjunction with developmental control, is discussed.

Acetates↗
PubMed2000

Spatial control of cell differentiation in Myxococcus xanthus.

Myxococcus xanthus develops species-specific multicellular fruiting bodies. Starting from a uniform mat of cells, some cells enter into nascent fruiting body aggregates, whereas other cells remain outside. The cells within the fruiting body differentiate from rods into spherical, heat-resistant spores, whereas the cells outside the aggregates, called peripheral cells, remain rod-shaped. Early developmentally regulated genes are expressed in peripheral cells as well as by cells in the fruiting bodies. By contrast, late developmental genes are only expressed by cells within the nascent fruiting bodies. The data show that peripheral cells begin to develop, but are unable to express genes that are switched on later than about 6 h after the start of development. All of the genes whose expression is limited to the fruiting body are dependent on C-signaling either directly or indirectly, whereas the genes that are equally expressed in peripheral rods and in fruiting body cells are not. One of the C-signal-dependent and spatially patterned operons is called dev, and the dev operon has been implicated in the process of sporulation. It is proposed that expression of certain genes, including those of the dev operon, is limited to the nascent fruiting body because fruiting body cells engage in a high level of C-signaling. Peripheral cells do less C-signaling than fruiting body cells, because they have a different spatial arrangement and are at lower density. As a consequence, peripheral cells fail to express the late genes necessary for spore differentiation.

Artificial Gene Fusion↗
PubMed1992

Gene expression in the Caenorhabditis elegans dauer larva: developmental regulation of Hsp90 and other genes.

Under conditions unfavorable to growth, the nematode Caenorhabditis elegans enters a developmentally arrested stage, the dauer larva. We have examined gene expression in the dauer larva and during recovery from the dauer stage. Run-on transcription assays with isolated nuclei reveal a depression of general RNA polymerase II transcription to 11-17% of that in other stages. Transcription of individual gene families (including actin, collagen, hsp70, and histone) is similarly depressed relative to actively growing stages. Dauer larvae are, however, capable of being induced for heat shock messages, indicating that they are competent to initiate and elongate transcripts. For most genes surveyed, reduced transcription in dauer larvae correlates with a decrease in message abundance. Hsp70 mRNA, however, is transcribed at lower rates but accumulates at levels comparable to those in other stages. Interestingly, dauer larvae are 15-fold enriched in a mRNA for a C. elegans hsp90 gene. Hsp90 mRNA accumulation is regulated at least in part by differential stability. Dauer larvae thus appear to have a unique pattern of gene expression. Upon placement in food, dauer larvae reenter the developmental pathway as late-stage larvae. Dauer recovery is accompanied by a temporally regulated sequence of gene expression. At least four distinct patterns of gene expression can be distinguished during exit from the dauer stage. Steady-state levels of hsp70 and polyubiquitin mRNA rise sharply within 75 min of recovery before declining by the fourth hour. Actin and histone mRNAs increase steadily following 2-4 hr of recovery, whereas myosin mRNA increases after 10 hr. In contrast, hsp90 mRNA declines sharply within the first 75 min of recovery. Changes in mRNA populations during dauer formation and exit may be physiologically relevant.

Animals↗
PubMed2001

Regional and developmental expression of Epm2a gene and its evolutionary conservation.

Lafora's disease, an autosomal recessive progressive myoclonus epilepsy, is caused by mutations in the EPM2A gene encoding a dual-specificity phosphatase (DSP) named laforin. Here, we analyzed the developmental and regional expression of murine Epm2a and discussed its evolutionary conservation. A phylogenetic analysis indicated that laforin is evolutionarily distant from other DSPs. Southern zoo blot analysis suggested that conservation of Epm2a gene is limited to mammals. Laforin orthologs (human, mouse, and rat) display more than 94% similarity. All missense mutations known in Lafora disease patients affect conserved residues, suggesting that they may be essential for laforin's function. Epm2a is expressed widely in various organs but not homogeneously in brain. The levels of Epm2a transcripts in mice brains increase postnatally, attaining its highest level in adults. The most intense signal was detected in the cerebellum, hippocampus, cerebral cortex, and the olfactory bulb. Our results suggest that Epm2a is functionally conserved in mammals and is involved in growth and maturation of neural networks.

Aging↗
PubMed2001

qBrn-2, a POU III gene in quail: distinct developmental expression revealed by a specific antibody.

We examined qBrn-2 protein expression in quail from its onset to final profile with a specific antibody we prepared. qBrn-2 expression employed onset-widespread-restriction pattern, and precisely concurred with formation and differentiation of neural tube. qBrn-2 protein was also located outside neural tube. Obvious differences in expression were observed compared with that of Brn-2.

Animals↗
PubMed2006

Developmental aberrations of liver gene expression in bovine fetuses derived from somatic cell nuclear transplantation.

Cloning by somatic cell nuclear transfer (NT) has been accomplished. However, the process itself is inefficient since most clones die before birth and survivors often display various anomalies. In an effort to determine global expression profiles of developmentally regulated liver genes in NT bovine fetuses, we employed a custom-made bovine liver complementary DNA (cDNA) microarray. The NT fetuses in early pregnancy were derived from cumulus cells as the nuclear donor cells. Normal fetuses were derived from in vitro fertilization (IVF) and artificial insemination (AI). Gene expression levels in NT, IVF, and AI fetal livers were obtained by comparing individual fetal liver samples with that of adult liver of nonpregnant cycling cows. Statistical analyses of the expression data showed widespread dysregulation of developmentally important genes in the three NT fetuses examined. It was found that the number of dysregulated genes was within a range of 3.5-7.7% of the tested genes in the NT fetal livers. The analyses revealed that one NT fetus was markedly different in liver gene expression profile from the other two NT fetal livers in which the expression profiles were highly correlated. Thus, our findings demonstrate that widespread dysregulation of liver genes occurs in the developing liver of NT bovine fetuses. It is possible that inappropriate genomic reprogramming after NT is a key factor associated with abnormal gene expressions in the livers of NT fetuses, whereas distinct expression patterns between the fellow cloned fetuses likely have resulted from variable epigenetic status of the donor nuclei.

Animals↗
PubMed1992

Isolation and sequence of a developmentally regulated putative novel gene, priA, from the basidiomycete Lentinus edodes.

Screening for gene(s) homologous to v-Ha-ras (Harvey rat sarcoma viral ras gene) in the basidiomycete, Lentinus edodes, resulted in the isolation of a novel gene (designated priA), in addition to a ras gene homologue [Hori et al., Gene 105 (1991) 91-96]. The priA gene has a coding capacity of 258 amino acids (aa) interrupted by two short putative introns. The 5'-upstream region of priA contains GGGCGG box, CCAAT box, TATAAA box and CT sequence elements in 5'----3' order. One transcription start point (tsp) was located 10 nucleotides upstream from a TATAAA box and another tsp just in a CT sequence. The deduced PRIA protein (26.7 kDa), rich in Ser (42 residues), Pro (29 residues) and Thr (27 residues), contained different types of putative zinc-binding motifs. It initiated with a hydrophobic aa sequence and terminated with the unique sequence, Cys-Aaa-Aaa-Xaa (where Aaa is aliphatic aa and Xaa is any aa), implying an association with the inner membrane surface via acylation of the Cys residue. The priA gene expression was found to be developmentally regulated with primordia/immature fruiting bodies having much higher levels of priA transcript. Preprimordial mycelia and mature fruiting bodies, however, contain very low levels of priA transcript. The priA gene may play a role during the beginning of fruiting.

Amino Acid Sequence↗