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At least 451 records · Page 25Linked to original sources
PubMed1997

Modulation of collagen gene expression by cytokines: stimulatory effect of transforming growth factor-beta1, with divergent effects of epidermal growth factor and tumor necrosis factor-alpha on collagen type I and collagen type IV.

Transforming growth factor-beta1 (TGF-beta1) is well recognized as a potent mediator of both fibrillar (collagen type I) and basement membrane (collagen type IV) production. However, tissue injury is characterized by the concomitant expression of many cytokines and/or growth factors in addition to TGF-beta1, and the ultimate extent of extracellular-matrix (ECM) deposition may reflect the interacting effects of TGF-beta1 and these other cytokines and/or growth factors. We, therefore, sought to determine whether other cytokines and/or growth factors, known to be produced after tissue injury, are capable either alone or in combination with TGF-beta1 of modulating collagen gene expression. Collagen type I and collagen type IV gene expression was assessed in NIH-3T3 cells, a murine fibroblast-like cell line that responds to TGF-beta1, with increases in both collagen type I and collagen type IV production. TGF-beta1 coordinately induced production of collagen type IV messenger ribonucleic acid (mRNA) to a level 3.8-fold above its baseline value (p < 0.001) and collagen type I mRNA to a level 2.6-fold above its baseline value (p < 0.001). Of the other cytokines and/or growth factors tested, only epidermal growth factor (EGF) had significant effects on collagen mRNA expression. We report the novel observation that EGF significantly induced collagen type IV mRNA (3.0-fold; p < 0.001) but did not alter collagen type I mRNA expression. Platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), and insulin-like growth factor-1 (IGF-1) did not alter the expression of mRNA for collagen type IV or collagen type I. Addition of TGF-beta1 to cytokine- and/or growth factor-treated cells increased both collagen type IV and collagen type I mRNA levels. However, collagen type IV mRNA levels were similar in cultures given TGF-beta1 alone and cultures given TGF-beta1 with other cytokines and/or growth factors; there were no additive, synergistic, or antagonistic effects after coadministration of TGF-beta1 and other cytokines and/or growth factors. With regard to collagen type I mRNA expression, all cytokines and/or growth factors tested, with the exception of TNF-alpha, had no effect on collagen type I mRNA levels in TGF-beta1-treated cultures. Importantly, TNF-alpha antagonized the stimulatory effect of TGF-beta1 on collagen type I mRNA levels. These observations support a dominant role for TGF-beta1 in stimulating coordinate expression of collagen type I and collagen type IV mRNAs by NIH-3T3 cells; EGF and TNF-alpha are capable of inducing divergent expression of the genes for these two types of collagen.

3T3 Cells↗
PubMedDate not supplied

Conservation and divergence of Bmp2a, Bmp2b, and Bmp4 expression patterns within and between dentitions of teleost fishes.

The diversity of tooth location in teleost fishes provides an excellent system for comparing genetic divergence between teeth in different species (phylogenetic homologs) with divergence between teeth within one species (iterative homologs). We have chosen to examine the expression of three members of the bone morphogenetic protein (Bmp) family because they are known to play multiple roles in tooth development and evolution in tetrapod vertebrates. We characterized expression of Bmp2a, Bmp2b, and Bmp4 during the development of oral and pharyngeal dentitions in three species of teleost fishes, the zebrafish (Danio rerio), Mexican tetra (Astyanax mexicanus), and Japanese medaka (Oryzias latipes). We found that expression in teleosts is generally highly conserved, with minor differences found among both iteratively homologous and phylogenetically homologous teeth. Expression of orthologous genes differs in several ways between the teeth of teleost fishes and those of the mouse, but between these vertebrate groups the summed expression pattern of Bmp genes is highly conserved. Significantly, the toothless oral region of the zebrafish lacks Bmp expression domains found in teleosts with oral teeth, implicating these genes in evolutionary tooth loss. We conclude that Bmp expression has been largely conserved in vertebrate tooth development over evolutionary time, and that loss of Bmp expression is correlated with region-specific loss of the dentition in a major group of fishes.

Animals↗
PubMed2025

Expression of De Novo Open Reading Frames in Natural Populations of Drosophila melanogaster.

De novo genes, which originate from noncoding DNA, are known to have a high rate of turnover over short evolutionary timescales, such as within a species. Thus, their expression is often lineage- or genetic background-specific. However, little is known about their levels and breadth of expression as populations of a species diverge. In this study, we utilized publicly available RNA-seq data to examine the expression of newly evolved open reading frames (neORFs) in comparison to non- and protein-coding genes in Drosophila melanogaster populations from the derived species range in Europe and the ancestral range in sub-Saharan Africa. Our datasets included two adult tissue types as well as whole bodies at two temperatures for both sexes and three larval/prepupal developmental stages in a single tissue and sex, which allowed us to examine neORF expression and divergence across multiple sample types as well as sex and population. We detected a relatively large proportion (approximately 50%) of annotated neORFs as expressed in the population samples, with neORFs often showing greater expression divergence between populations than non- or protein-coding genes. However, differential expression of neORFs between populations tended to occur in a sample type-specific manner. On the other hand, neORFs displayed less sex-biased expression than the other two gene classes, with the majority of sex-biased neORFs detected in whole bodies, which may be attributable to the presence of the gonads. We also found that neORFs shared among multiple lines in the original set of inbred lines in which they were first detected were more likely to be both expressed and differentially expressed in the new population samples, suggesting that neORFs at a higher frequency (i.e. present in more individuals) within a species are more likely to be functional.

Animals↗
PubMed2004

Differential up-regulation of cytosolic and membrane-bound heat shock protein 70 in tumor cells by anti-inflammatory drugs.

PURPOSE: Modulation of the heat shock protein (HSP) response affects sensitivity to therapeutic agents in cancer. Here, drugs with anti-inflammatory potential (cyclooxygenase 1/2 inhibitors) and peroxidase proliferator-activated receptor-gamma agonists were analyzed for their capacity to affect Hsp70 expression in human cancer cells with a divergent Hsp70 membrane expression pattern. EXPERIMENTAL DESIGN: In dose kinetics, the nonlethal concentration of acetyl-salicyl acid, celecoxib, rofecoxib, and the insulin-sensitizer pioglitazone was identified for the human adenocarcinoma cell line CX-. With the exception of CLX, which was diluted in DMSO, all reagents were dissolved in water. After treatment with the different compounds at nontoxic concentrations for 6 h, followed by a 1-h recovery period, the cytosolic Hsp70 levels were measured in CX-2 and CX- tumor cells by Western blot analysis. Fold increase was calculated in relation to the housekeeping protein tubulin. Membrane-bound Hsp70 was analyzed by flow cytometry using a FITC-labeled Hsp70-specific monoclonal antibody. Untreated cells and cells incubated with equivalent amounts of the diluting agents served as controls. The immunological function was tested in granzyme B apoptosis assays, standard (51)Cr release assays, and antibody blocking studies. RESULTS: Compared with aqua dest, the cytoplasmic amount of Hsp70 was equally enhanced in CX-2 and CX- cells by all compounds. An increase in membrane-bound Hsp70, detected selectively in CX- cells, corresponded to an enhanced sensitivity to granzyme B- and natural killer cell-mediated kill that was blockable by using a Hsp70-specific antibody. CONCLUSIONS: Although increase in cytosolic Hsp70 levels conferred resistance to further stress, membrane-bound Hsp70 rendered tumor cells more sensitive to the immunological attack mediated by granzyme B and natural killer cells. Our data provide a biological rational for combining anti-inflammatory drugs with immunotherapy in cancer therapy.

Anti-Inflammatory Agents↗
PubMed2026

Gene expression is stable despite widespread cis and trans regulatory divergence in Saccharomyces yeasts.

Regulatory evolution can alter phenotypes, but cis- and trans-regulatory mechanisms may also diverge extensively while total transcript abundance remains stable. Comparisons of parental expression with allele-specific expression in F1 hybrids provide a framework for separating cis- and trans-regulatory effects because both parental alleles are measured in a shared trans-regulatory environment. Here, we analyzed RNA sequencing data from Saccharomyces cerevisiae, Saccharomyces paradoxus, and their F1 hybrid. Among the 4,164 genes with sufficient allele-specific support for strict classification, 2,134 (51.2%) showed detectable cis and/or trans regulatory divergence. However, hybrid expression remained largely conserved, with 81.5% of genes not significantly different from either parent. Compensatory cis-trans divergence predominated over reinforcing divergence; cross-replicate estimation reduced the apparent magnitude of this excess, but opposite-sign effects remained predominant in all 20 non-overlapping replicate comparisons. To connect gene expression to genome sequence, we analyzed the strongly cis-diverged locus LYS2 and found species differences in promoter architecture, including an S. cerevisiae-specific AT-rich insertion, altered spacing among candidate regulatory features, and a promoter-proximal TATA-like element unique to S. cerevisiae. Sequence-based nucleosome prediction suggests that these differences create a broader promoter-proximal nucleosome-depleted region in S. cerevisiae than in S. paradoxus. We also quantified allele-resolved intron retention and found that allele-resolved intron retention was broadly conserved, with only rare locus-specific hybrid-associated shifts. Together, these results show that regulatory divergence is widespread but often buffered in the hybrid, whereas intron-retention divergence is comparatively limited.

Saccharomyces↗
PubMed2026

Nonadditive gene expression and reduced homoeolog expression bias in an intraspecific hexaploid wheat hybrid.

BACKGROUND: Intraspecific hybridization in allopolyploid plants can generate additive and nonadditive changes in gene expression through interactions between divergent parental genomes. However, how it simultaneously affects gene expression and the relative expression of homoeologs in higher-order polyploids is less well understood. To study this, we sequenced seedling leaf transcriptomes and profiled gene body methylation in two hexaploid wheat (Triticum aestivum L.) cultivars and their F&#x2081; hybrids. RESULTS: Although only 4.3% of genes differed in expression between the parents, 22.3% deviated from mid-parent expression in the hybrids, with many showing transgressive expression. 32.1% of triads contained at least one homoeolog that deviated from mid-parent expression, and all three homoeologs deviated in 11% of triads, substantially more than expected by chance. Triads in which all three homoeologs were overexpressed also showed reduced differences in expression among homoeologs. Greater parental divergence in relative homoeolog expression was associated with nonadditive expression. Genes lacking gene body methylation were also more likely to show dominant or transgressive expression, whereas gene body methylation was associated with more balanced homoeolog expression and additive or conserved expression. CONCLUSIONS: Intraspecific hybridization in hexaploid wheat, even without a change in ploidy, was associated with widespread nonadditive gene expression and altered relative homoeolog expression within triads. These responses were associated with parental differences in homoeolog expression and the absence of gene body methylation. Although our findings are limited to seedling leaves from a single intraspecific cross, they provide a basis for testing the generality of these patterns across tissues, developmental stages, and genetic backgrounds.

Triticum↗
PubMed1992

Divergent effects of glucocorticoid on the gene expression of vasoactive intestinal peptide in the rat cerebral cortex and pituitary.

We investigated the effects of glucocorticoid on the expression of the vasoactive intestinal peptide (VIP) gene, a neuropeptide and an established prolactin (PRL)-releasing factor, in the rat brain and pituitary. The mRNA and peptide contents of VIP in the cerebral cortex, hypothalamus and anterior pituitary of male Sprague-Dawley rats were quantitated 4 weeks after adrenalectomy or sham-operation. Following adrenalectomy, VIP mRNA content increased in the anterior pituitary but showed no significant change in the cerebral cortex and hypothalamus. Dexamethasone treatment for 10 days abolished the effect of adrenalectomy and decreased significantly pituitary VIP mRNA content in sham-operated rats. In the cerebral cortex, however, dexamethasone treatment resulted in an enhancement in VIP mRNA levels in both sham-operated and adrenalectomized animals. Hypothalamic VIP mRNA content remained unchanged. These changes in VIP mRNA levels were accompanied by parallel changes in VIP concentrations in the tissues studied, suggesting that glucocorticoid regulates the synthesis of VIP in the cerebral cortex and anterior pituitary. On the other hand, serum PRL level increased after adrenalectomy but became suppressed following dexamethasone administration, in parallel with changes in pituitary VIP synthesis. These findings suggest that the effect of glucocorticoid on PRL secretion may be mediated, at least in part, via changes in VIP synthesis and secretion. We conclude that glucocorticoid regulates the expression of VIP in the rat brain, resulting in divergent changes in the cerebral cortex and pituitary. Changes in VIP synthesis and secretion may contribute to the disturbances in brain function and PRL secretion in conditions of glucocorticoid excess.

Adrenalectomy↗
PubMed2003

Conservation of Endo16 expression in sea urchins despite evolutionary divergence in both cis and trans-acting components of transcriptional regulation.

Evolutionary changes in transcriptional regulation undoubtedly play an important role in creating morphological diversity. However, there is little information about the evolutionary dynamics of cis-regulatory sequences. This study examines the functional consequence of evolutionary changes in the Endo16 promoter of sea urchins. The Endo16 gene encodes a large extracellular protein that is expressed in the endoderm and may play a role in cell adhesion. Its promoter has been characterized in exceptional detail in the purple sea urchin, Strongylocentrotus purpuratus. We have characterized the structure and function of the Endo16 promoter from a second sea urchin species, Lytechinus variegatus. The Endo16 promoter sequences have evolved in a strongly mosaic manner since these species diverged approximately 35 million years ago: the most proximal region (module A) is conserved, but the remaining modules (B-G) are unalignable. Despite extensive divergence in promoter sequences, the pattern of Endo16 transcription is largely conserved during embryonic and larval development. Transient expression assays demonstrate that 2.2 kb of upstream sequence in either species is sufficient to drive GFP reporter expression that correctly mimics this pattern of Endo16 transcription. Reciprocal cross-species transient expression assays imply that changes have also evolved in the set of transcription factors that interact with the Endo16 promoter. Taken together, these results suggest that stabilizing selection on the transcriptional output may have operated to maintain a similar pattern of Endo16 expression in S. purpuratus and L. variegatus, despite dramatic divergence in promoter sequence and mechanisms of transcriptional regulation.

Animals↗
PubMed2003

Temporal divergence in the pattern of messenger RNA expression in bovine embryos cultured from the zygote to blastocyst stage in vitro or in vivo.

The objective of this study was to examine the time during the postfertilization period that gene expression patterns in in vitro-cultured bovine embryos diverge from those of their in vivo-cultured counterparts. Presumptive bovine zygotes were produced by in vitro maturation and fertilization of immature oocytes collected from the ovaries of slaughtered animals. Approximately 20 h post insemination (hpi), zygotes were denuded and randomly divided into two groups for culture either in vitro, in synthetic oviduct fluid medium, or in vivo, in the ewe oviduct. Embryos were recovered from both systems at approximately 30 hpi (2-cell), 2 (4-cell), 3 (8-cell), 4 (16-cell), 5 (early morula), 6 (compact morula), or 7 (blastocyst) days post insemination. On recovery, they were examined for stage of development and snap frozen in liquid nitrogen for the analysis of transcript abundance using real-time polymerase chain reaction. The transcripts studied were glucose transporter 5, sarcosine oxidase, mitochondrial Mn-superoxide dismutase, connexin 43, interferon tau, insulin-like growth factor II, apoptosis regulator box-alpha and insulin-like growth factor-I receptor, most of which are known from our previous work to differ in terms of transcript abundance in blastocysts derived from culture in vitro or in vivo. The results demonstrate that the relative abundance of the transcripts studied varies throughout the preimplantation period and is strongly influenced by the culture environment. In addition, the data demonstrate that changes in transcript abundance in blastocyst stage embryos are in many cases a consequence of perturbed transcription earlier in development. Depending on the transcript, these differences may be evident by as little as 10 h of initiation of culture. Such information has implications not only for basic biology but also for human assisted reproduction in which there is a move toward culturing embryos to the blastocyst stage, necessitating prolonged culture in vitro under potentially deleterious conditions.

Animals↗
PubMed2006

Delineation of matriptase protein expression by enzymatic gene trapping suggests diverging roles in barrier function, hair formation, and squamous cell carcinogenesis.

The membrane serine protease matriptase is required for epidermal barrier function, hair formation, and thymocyte development in mice, and dysregulated matriptase expression causes epidermal squamous cell carcinoma. To elucidate the specific functions of matriptase in normal and aberrant epidermal differentiation, we used enzymatic gene trapping combined with immunohistochemical, ultrastructural, and barrier function assays to delineate the spatio-temporal expression and function of matriptase in mouse keratinized tissue development, homeostasis, and malignant transformation. In the interfollicular epidermis, matriptase expression was restricted to postmitotic transitional layer keratinocytes undergoing terminal differentiation. Matriptase was also expressed in keratinizing oral epithelium, where it was required for oral barrier function, and in thymic epithelium. In all three tissues, matriptase colocalized with profilaggrin. In staged embryos, the onset of epidermal matriptase expression coincided with that of profilaggrin expression and acquisition of the epidermal barrier. In marked contrast to stratifying keritinized epithelium, matripase expression commenced already in undifferentiated and rapidly proliferating profilaggrin-negative matrix cells and displayed hair growth cycle-dependent expression. Exposure of the epidermis to carcinogens led to the gradual appearance of matriptase in a keratin-5-positive proliferative cell compartment during malignant progression. Combined with previous studies, these data suggest that matriptase has diverging functions in the genesis of stratified keratinized epithelium, hair follicles, and squamous cell carcinoma.

Animals↗
PubMed1988

A gene encoding the major beta tubulin of the mitotic spindle in Physarum polycephalum plasmodia.

The multinucleate plasmodium of Physarum polycephalum is unusual among eucaryotic cells in that it uses tubulins only in mitotic-spindle microtubules; cytoskeletal, flagellar, and centriolar microtubules are absent in this cell type. We have identified a beta-tubulin cDNA clone, beta 105, which is shown to correspond to the transcript of the betC beta-tubulin locus and to encode beta 2 tubulin, the beta tubulin expressed specifically in the plasmodium and used exclusively in the mitotic spindle. Physarum amoebae utilize tubulins in the cytoskeleton, centrioles, and flagella, in addition to the mitotic spindle. Sequence analysis shows that beta 2 tubulin is only 83% identical to the two beta tubulins expressed in amoebae. This compares with 70 to 83% identity between Physarum beta 2 tubulin and the beta tubulins of yeasts, fungi, alga, trypanosome, fruit fly, chicken, and mouse. On the other hand, Physarum beta 2 tubulin is no more similar to, for example, Aspergillus beta tubulins than it is to those of Drosophila melanogaster or mammals. Several eucaryotes express at least one widely diverged beta tubulin as well as one or more beta tubulins that conform more closely to a consensus beta-tubulin sequence. We suggest that beta-tubulins diverge more when their expression pattern is restricted, especially when this restriction results in their use in fewer functions. This divergence among beta tubulins could have resulted through neutral drift. For example, exclusive use of Physarum beta 2 tubulin in the spindle may have allowed more amino acid substitutions than would be functionally tolerable in the beta tubulins that are utilized in multiple microtubular organelles. Alternatively, restricted use of beta tubulins may allow positive selection to operate more freely to refine beta-tubulin function.

Animals↗
PubMed1987

Structure, expression, and molecular mapping of a divergent member of the class I HLA gene family.

A class I gene distinct from HLA-A, -B, or -C was identified in a cosmid clone and transfected into mouse L cells. The gene, placed adjacent to the polyoma enhancer, produced a full-length class I mRNA and high levels of a 43-kDa protein in the cytoplasm. The surface expression of the gene product required its association with human beta 2-microglobulin. The protein was recognized by a xenoantiserum raised against a mixture of human B- and T-cell lines. The product was also serologically reactive with the HLA framework monoclonal antibodies. The complete nucleotide sequence of the gene was determined and a specific oligonucleotide probe was synthesized. This probe was used to identify a full-length mRNA transcript in a B-lymphoblastoid cell line (JY). The gene was mapped within a 190-kilobase Not I restriction fragment located in the telomeric portion of the human major histocompatibility complex. Distinct features of the gene include the structure of the promoter, the position of the translation initiation site, a frameshift mutation at the carboxyl terminus, the insertion of an Alu repeat element in the eighth exon, divergence in the derived amino acid sequence, and the lack of expression of the gene in some cells.

Amino Acid Sequence↗
PubMed2003

Two azuki bean XTH genes, VaXTH1 and VaXTH2, with similar tissue-specific expression profiles, are differently regulated by auxin.

To gain insight into the functional diversity of the XTH (xyloglucan endotransglucosylase/hydrolase) gene family, we analyzed the expression profiles of two azuki bean genes, VaXTH1 and VaXTH2, which share a striking resemblance in their amino acid sequences. The two XTH genes exhibit essentially similar tissue-specific expression profiles, in that both mRNAs are found predominantly in the phloem fibers of growing internodes. However, their expression profiles are not identical. Whereas VaXTH1 is expressed in xylem cells in the basal part of the internode, little or no expression of VaXTH2 is found in the xylem. Furthermore, they exhibit spatially divergent RNA distribution profiles along the internode, VaXTH1 being expressed nearer to the top of the internode than VaXTH2. This indicates their temporally divergent expression profiles during development of the phloem fiber. Indole-3-acetic acid (IAA) up-regulates both of the mRNA levels. However, this effect of IAA on the VaXTH1 gene is nullified in 0.25 M mannitol, which prevents cell expansion without affecting auxin action per se. In contrast, the IAA-induced up-regulation of the VaXTH2 gene is not affected by mannitol. Furthermore, fusicoccin, which promotes acidification and growth, up-regulates VaXTH1 expression, but not VaXTH2 expression. Thus, the two XTH genes are committed to different steps of the cell wall dynamics in the same cell type at different stages of phloem fiber development, and are regulated by IAA in different ways.

Fabaceae↗
PubMed1998

Regulation of SPARC expression during early Xenopus development: evolutionary divergence and conservation of DNA regulatory elements between amphibians and mammals.

SPARC (Secreted Protein, Acidic, Rich in Cysteine/osteonectin/BM-40) is a highly conserved metal-binding extracellular matrix (ECM) glycoprotein which is first expressed by Xenopus embryos during late gastrulation/early neurulation (stage 12/13), by presumptive notochord and somitic cells. When animal cap explants of stage 9 embryos were cultured in vitro, SPARC expression was not detected until sibling embryos reached late neurula stage (stage 19). Addition of activin, a potent dorsal mesoderm inducer, to animal caps resulted in SPARC being expressed by the time sibling embryos reached stage 16. While basic fibroblast growth factor (bFGF), a ventral mesoderm inducer, had modest effects on SPARC mRNA expression, the combination of both activin and bFGF was synergistic. The appearance, however, of SPARC transcripts 11 h after the addition of activin and bFGF, indicates that unknown intermediates were likely to be involved in activating SPARC expression. In order to identify the potential intermediate regulatory factors which may activate and control SPARC expression, we examined the genomic organization of the 5' end of the Xenopus SPARC gene. No significant homology to the equivalent region that is highly conserved in the mouse, bovine and human SPARC genes was observed. Thus, while mammalian SPARC promoters lack TATA or CAAT boxes, the Xenopus gene contains a consensus TATA box. Moreover, promoter-proximal GGA-box repeats necessary for high level expression of mammalian SPARC are absent in Xenopus. When reporter constructs containing the 5' flanking region of the Xenopus gene were microinjected into two-cell embryos, 868 bp of 5' flanking DNA was sufficient to mimic the temporal and tissue-specific pattern of SPARC expression observed in whole embryos. While a bovine SPARC promoter reporter construct containing 740 bp of the 5' flanking DNA was expressed at a significant level in Xenopus embryos, significant differences in the cell-type expression of the reporter genes were obtained between the bovine and Xenopus constructs. The data indicate that zygotic activation of SPARC mRNA is mediated by regulatory factors acting downstream of major mesoderm induction events. The high DNA sequence conservation at the 5' end of mammalian SPARC genes is not conserved in Xenopus. These differences led to differences in their ability to direct tissue-specific gene expression in early Xenopus embryos.

Activins↗
PubMed1987

Free intermingling of mammalian beta-tubulin isotypes among functionally distinct microtubules.

Mammalian cells express a spectrum of tubulin isotypes whose relationship to the diversity of microtubule function is unknown. To examine whether different isotypes are segregated into functionally distinct microtubules, we generated immune sera capable of discriminating among the various naturally occurring beta-tubulin isotypes. Cloned fusion proteins encoding each isotype were used first to tolerogenize animals against shared epitopes, and then as immunogens to elicit a specific response. In experiments using these sera, we show that there is neither complete nor partial segregation of beta-tubulin isotypes: both interphase cytoskeletal and mitotic spindle microtubules are mixed copolymers of all expressed beta-tubulin isotypes. Indeed, a highly divergent isotype normally expressed only in certain hematopoietic cells is also indiscriminately assembled into all microtubules both in their normal context and when transfected into HeLa cells.

Animals↗
PubMed1988

Expression patterns of the homeo box-containing genes En-1 and En-2 and the proto-oncogene int-1 diverge during mouse development.

We have compared the expression of the murine genes En-1,En-2, and in-1 during development by in situ hybridization. Expression of all three genes was first detected at 8.0 days in overlapping bands of the anterior neural folds. By 12.0 days the expression patterns diverged. En-1 and En-2 were expressed in a similar ring of cells in the central nervous system (CNS) at the midbrain/hindbrain junction. En-1 was also expressed de novo in two lateral stripes extending the length of the hindbrain and spinal cord, in the developing vertebral column, in two lateral stripes of dermatome-derived cells, and in the tail and limb buds. By 12.0 days int-1 expression showed little overlap with the En genes and could not be detected at later stages. At 15.5 days En gene expression was primarily limited to the midbrain/hindbrain in overlapping but nonidentical sets of differentiated cells. In the adult, En-1 and En-2 marked the same sets of cells in the pons, but En-2 alone was detected in the granular layer of the cerebellum. The results are consistent with int-1 and the En genes playing a role early in development in defining spatial domains in the CNS. Later in development the En genes may have an additional function in neurogenesis. En-1 expression in the developing pericordal tube suggests that it may also be involved in vertebral assembly.

Animals↗
PubMed2002

Expression profiling of reciprocal maize hybrids divergent for cold germination and desiccation tolerance.

Recombinant inbred lines (RILs) derived from B73 x M017 were screened for cold germination (CG) and desiccation tolerance (DT) phenotypes. Reciprocal F(1) hybrids were made between divergent RILs, and hybrids that showed differential phenotypes (parent-of-origin effect) for CG or DT were selected for profiling mRNA and protein expression. mRNA and proteins were extracted from embryo axes of seed germinated for 11 d at 12.5 degrees C in the dark and developing embryos at 40% seed moisture (R5 stage) for CG and DT, respectively. GeneCalling analysis, an open-ended mRNA profiling method, identified 336 of 32,496 and 656 of 32,940 cDNA fragments that showed >or=1.5-fold change in expression between the reciprocal F(1) hybrids for CG and DT, respectively. Protein expression map (PEM) analysis, an open-ended two-dimensional polyacrylamide gel electrophoresis, identified 117 of 2,641 and 205 of 1,876 detected proteins to be differentially expressed with >or=1.5-fold change between the reciprocal F(1) hybrids in CG and DT samples, respectively. A subset of these proteins was identified by tandem mass spectrometry followed by database query of the spectra. The differentially expressed genes/proteins were classified into various functional groups including carbohydrate and amino acid metabolism, ion transporters, stress and defense response, polyamine metabolism, chaperonins, cytoskeleton associated, etc. Phenotypic analysis of seed from self-pollinated ears of the reciprocal F(1) hybrids displayed small differences compared with the reciprocal hybrids themselves, suggesting a negligible effect of cytoplasmic factors on CG and DT traits. The results provide leads to improving our understanding of the genes involved in stress response during seed maturation and germination.

Acclimatization↗
PubMed1991

Segmentation gene expression in the housefly Musca domestica.

Drosophila and Musca both belong to the group of higher dipteran flies and show morphologically a very similar early development. However, these two species are evolutionary separated by at least 100 million years. This presents the opportunity for a comparative analysis of segmentation gene expression across a large evolutionary distance in a very similar embryonic background. We have analysed in detail the early expression of the maternal gene bicoid, the gap genes hunchback, Krüppel, knirps and tailless, the pair-rule gene hairy, the segment-polarity gene engrailed and the homoeotic gene Ultrabithorax. We show that the primary expression domains of these genes are conserved, while some secondary expression aspects have diverged. Most notable is the finding of hunchback expression in 11-13 stripes shortly before gastrulation, as well as a delayed expression of terminal domains of various genes. We conclude that the early developmental gene hierarchy, as it has been defined in Drosophila, is evolutionary conserved in Musca domestica.

Animals↗