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PubMed2005

Diverse spatial, temporal, and sexual expression of recently duplicated androgen-binding protein genes in Mus musculus.

BACKGROUND: The genes for salivary androgen-binding protein (ABP) subunits have been evolving rapidly in ancestors of the house mouse Mus musculus, as evidenced both by recent and extensive gene duplication and by high ratios of nonsynonymous to synonymous nucleotide substitution rates. This makes ABP an appropriate model system with which to investigate how recent adaptive evolution of paralogous genes results in functional innovation (neofunctionalization). RESULTS: It was our goal to find evidence for the expression of as many of the Abp paralogues in the mouse genome as possible. We observed expression of six Abpa paralogues and five Abpbg paralogues in ten glands and other organs located predominantly in the head and neck (olfactory lobe of the brain, three salivary glands, lacrimal gland, Harderian gland, vomeronasal organ, and major olfactory epithelium). These Abp paralogues differed dramatically in their specific expression in these different glands and in their sexual dimorphism of expression. We also studied the appearance of expression in both late-stage embryos and postnatal animals prior to puberty and found significantly different timing of the onset of expression among the various paralogues. CONCLUSION: The multiple changes in the spatial expression profile of these genes resulting in various combinations of expression in glands and other organs in the head and face of the mouse strongly suggest that neofunctionalization of these genes, driven by adaptive evolution, has occurred following duplication. The extensive diversification in expression of this family of proteins provides two lines of evidence for a pheromonal role for ABP: 1) different patterns of Abpa/Abpbg expression in different glands; and 2) sexual dimorphism in the expression of the paralogues in a subset of those glands. These expression patterns differ dramatically among various glands that are located almost exclusively in the head and neck, where the sensory organs are located. Since mice are nocturnal, it is expected that they will make extensive use of olfactory as opposed to visual cues. The glands expressing Abp paralogues produce secretions (lacrimal and salivary) or detect odors (MOE and VNO) and thus it appears highly likely that ABP proteins play a role in olfactory communication.

Amino Acid Sequence↗
PubMed1990

Blocking cell division does not remove the requirement for Polycomb function in Drosophila embryogenesis.

The Polycomb (Pc) gene is required from the extended germ band stage onwards, to maintain spatially restricted patterns of homeotic gene expression. It has been thought to be involved in the 'stable inheritance of the determined state'. In this paper, we have tested the notion that the Pc gene is required specifically during or after DNA replication to enable the stable transmission of states of gene activity. We found that arresting cell division using the string mutation or blocking DNA replication with aphidicolin failed to prevent ectopic expression of the homeotic gene Ultrabithorax in Pc mutants. Thus, even in the absence of DNA replication, Pc is required to maintain spatially restricted patterns of homeotic gene expression. The role of the Pc gene product in the stable repression of homeotic gene transcription is discussed.

Animals↗
PubMed2002

MEX-3 interacting proteins link cell polarity to asymmetric gene expression in Caenorhabditis elegans.

The KH domain protein MEX-3 is central to the temporal and spatial control of PAL-1 expression in the C. elegans early embryo. PAL-1 is a Caudal-like homeodomain protein that is required to specify the fate of posterior blastomeres. While pal-1 mRNA is present throughout the oocyte and early embryo, PAL-1 protein is expressed only in posterior blastomeres, starting at the four-cell stage. To better understand how PAL-1 expression is regulated temporally and spatially, we have identified MEX-3 interacting proteins (MIPs) and characterized in detail two that are required for the patterning of PAL-1 expression. RNA interference of MEX-6, a CCCH zinc-finger protein, or SPN-4, an RNA recognition motif protein, causes PAL-1 to be expressed in all four blastomeres starting at the four-cell stage. Genetic analysis of the interactions between these mip genes and the par genes, which provide polarity information in the early embryo, defines convergent genetic pathways that regulate MEX-3 stability and activity to control the spatial pattern of PAL-1 expression. These experiments suggest that par-1 and par-4 affect distinct processes. par-1 is required for many aspects of embryonic polarity, including the restriction of MEX-3 and MEX-6 activity to the anterior blastomeres. We find that PAL-1 is not expressed in par-1 mutants, because MEX-3 and MEX-6 remain active in the posterior blastomeres. The role of par-4 is less well understood. Our analysis suggests that par-4 is required to inactivate MEX-3 at the four-cell stage. Thus, PAL-1 is not expressed in par-4 mutants because MEX-3 remains active in all blastomeres. We propose that MEX-6 and SPN-4 act with MEX-3 to translate the temporal and spatial information provided by the early acting par genes into the asymmetric expression of the cell fate determinant PAL-1.

Animals↗
PubMed1991

Fibronectin and collagen gene expression in healing experimental colonic anastomoses.

The temporal and spatial expression of fibronectin and type I and III collagen genes were studied 1-14 days after surgery in the healing rat colonic anastomosis using recombinant deoxyribonucleic acid techniques. Messenger ribonucleic acids (mRNAs) coding for fibronectin and type III collagen synthesis increased from the first day after operation and type I collagen synthesis increased from the second day after operation, as demonstrated by Northern hybridizations. Maximal mRNA production for fibronectin and collagens was seen at 2 and 7 days, respectively, after anastomosis. Activation of type I and III collagen genes in the anastomotic area was confined to tissues developing in the anastomotic line, the serosal surface and the submucosal layer. Strong fibronectin expression was observed in the same areas. The results suggest that genetic events leading to collagen synthesis in the anastomotic area start immediately after surgery. Maximal gene expression is not reached until 1 week after surgery.

Anastomosis, Surgical↗
PubMed1989

The promoter region of the Drosophila alpha 2-tubulin gene directs testicular and neural specific expression.

The temporal and spatial expression pattern of the Drosophila melanogaster alpha 2-tubulin gene (alpha 2) has been investigated by examining the expression of an alpha 2-lacZ fusion gene. When this fusion gene is introduced into the germ line by P-element mediated transformation, expression is only detected in chordotonal organs and testes. Chordotonal organs, which are sensory organs of the peripheral nervous system, express the gene from late embryonic through adult stages in both males and females. Testicular expression occurs from larval through adult stages and is limited to germ-line cells, the primary and secondary spermatocytes and perhaps the early spermatids.

Animals↗
PubMed1992

Differential expression of two MADS box genes in wild-type and mutant petunia flowers.

We isolated and characterized two flower-specific genes from petunia. The protein products of these genes, designated floral binding protein 1 (FBP1) and 2 (FBP2), are putative transcription factors with the MADS box DNA binding domain. RNA gel blot analysis showed that the fbp1 gene is exclusively expressed in petals and stamen of petunia flowers. In contrast, the FBP1 protein was only detectable in petals and not in stamens, suggesting post-transcriptional regulation of the fbp1 gene in these tissues. The fbp2 gene is expressed in petals, stamen, carpels, and at a very low level in sepals but not in vegetative tissues. We analyzed the spatial expression of these fbp genes in floral organs of two homeotic flower mutants. In the blind mutant, whose flower limbs are transformed into antheroid structures on top of normal tubes, identical expression levels of both genes were observed in the antheroid structures as in normal anthers. In the homeotic mutant green petals, the petals are replaced by sepaloid organs in which the expression of fbp1 is strongly reduced but not completely abolished. Our results suggest a regulation of the fbp1 gene expression by the green petals (gp) gene. Expression of the fbp2 gene was not affected in the green petals mutant. In contrast to the proposed models describing floral morphogenesis, our data indicated that homeotic genes can be functional in one whorl only.

Amino Acid Sequence↗
PubMed1994

The LOX1 Gene of Arabidopsis Is Temporally and Spatially Regulated in Germinating Seedlings.

We examined the temporal and spatial expression patterns of the LOX1 gene during the development of Arabidopsis thaliana seedlings. Measurements of steady-state LOX1 mRNA levels indicated that this gene is transiently expressed during germination. LOX1 mRNA was not detected in seed that had imbibed (T0) but reached a maximum level by 1 d in both light- and dark-grown seedlings. The induction of the LOX1 gene was not light dependent; however, mRNA levels were 4-fold greater in light-grown seedlings. Immunoblot analysis of lipoxygenase protein levels and measurements of enzyme activity suggested that the induction of the LOX1 gene resulted in the production of functional lipoxygenase enzyme. Lipoxygenase protein was not present in dry seed or seed that had imbibed, but was first detected by immunoblot analysis after 1 and 2 d of growth in the light and dark, respectively. In both cases, lipoxygenase protein levels remained high for 2 d and then declined. Lipoxygenase activity paralleled the changes in protein levels. In situ hybridization studies revealed that the LOX1 gene is transiently expressed in the epidermis and the aleurone layer during germination. LOX1 mRNA levels were particularly high in the epidermis of the radicle and the adaxial side of the cotyledons. These results suggest that the LOX1 gene product is produced specifically during early germination and plays a role in the functioning of the epidermis.

Journal Article↗
PubMed1995

Temporal and spatial alterations in uterine estrogen receptor and progesterone receptor gene expression during the estrous cycle and early pregnancy in the ewe.

Mechanisms regulating responses of the ovine uterus to endocrine and paracrine signals during the estrous cycle and pregnancy are likely to require tissue- and cell-specific regulation of steroid hormone receptor gene expression. To determine effects of day and pregnancy status (cyclic or pregnant) on uterine estrogen receptor (ER) and progesterone receptor (PR) gene expression, ewes were hysterectomized either on Day 1 (Day 0 = estrus/mating), 6, 11, 13, or 15 of the estrous cycle (n = 3/day) or on Day 11, 13, 15, 17, or 25 of early pregnancy (n = 5/day). Steady state levels of ER and PR mRNA were determined in endometrial and myometrial tissues by slot-blot hybridization and ribonuclease protection assays, respectively, using homologous ovine ER and PR cRNA probes. Changes in spatial expression of ER and PR mRNA and protein in uterine tissue sections were determined by in situ hybridization and immunocytochemical analyses. In cyclic ewes, steady state levels of endometrial ER mRNA were highest on Day 1, declined between Days 1 and 6, and increased between Days 11 and 15. However in pregnant ewes, endometrial ER mRNA levels decreased between Days 11 and 15 and increased slightly between Days 15 and 25. In cyclic ewes, levels of myometrial ER mRNA were highest on Day 1, decreased to Day 6, and remained low thereafter. In cyclic ewes, endometrial PR mRNA levels were highest on Day 1, decreased between Days 1 and 11, and then increased between Days 13 and 15. In cyclic ewes, myometrial PR mRNA levels were highest on Day 1 and declined thereafter. Endometrial PR mRNA levels were not different between cyclic and pregnant ewes on Days 11, 13, and 15. In pregnant ewes, PR mRNA levels were low on Day 11, increased between Days 11 and 17, and decreased between Days 17 and 25. In pregnant ewes, myometrial PR mRNA levels were low and did not change between Days 11 and 25. In situ hybridization and immunocytochemical analyses revealed distinct tissue- and cell type-specific alterations in uterine ER and PR mRNA and protein expression during the estrous cycle and early pregnancy that generally paralleled overall changes in steady state levels of ER and PR mRNAs. In the endometrium, the most striking observation was that PR mRNA and protein expression disappeared from the luminal and shallow glandular epithelium between Days 6 and 13 of the estrous cycle, whereas ER mRNA and protein expression was low on Days 6 and 11 and increased between Days 11 and 15 in the luminal and shallow glandular epithelium. During early pregnancy, expression of ER and PR mRNAs, as well as ER and PR protein, was very low or absent in the luminal and shallow glandular epithelium between Days 13 and 25 of pregnancy. Moreover, ER and PR mRNA and protein were consistently present at low levels in the stroma and deep glandular epithelium in both cyclic (Days 11-15) and pregnant (Days 11-25) ewes. Collectively, results suggest that uterine ER and PR gene expression is regulated in a tissue- and cell type-specific manner during the estrous cycle and early pregnancy.

Animals↗
PubMed2003

Quantitation of a Glyptapanteles indiensis polydnavirus gene expressed in parasitized host, Lymantria dispar, by real-time quantitative RT-PCR.

Glyptapanteles indiensis is a polydnavirus-carrying wasp that parasitizes early instar gypsy moth larvae. During oviposition, the wasp injects calyx fluid containing polydnavirus along with its eggs into the host. Within the host, expression of polydnavirus genes triggers a set of changes in host physiology, which are of critical importance for the survival of the wasp. In the present study, a G. indiensis polydnavirus (GiPDV) gene, represented by cDNA clone GiPDV 1.1, was selected for expression analysis in the parasitized host. The GiPDV 1.1 gene transcript was detected in host hemolymph 30 min post-parasitization (pp) and continued to be detected for six days. The level of GiPDV 1.1 expression varied in different host tissues and expression in the brain was lower than in the hemolymph. The findings suggest that GiPDV 1.1 could be involved in early protection of parasitoid eggs from host cellular encapsulation. The temporal and spatial variations in PDV gene expression in different host tissues post-parasitization affirm their specific host regulation mechanism.

Amino Acid Sequence↗
PubMedDate not supplied

Arrays in rays: terminal addition in echinoderms and its correlation with gene expression.

The echinoderms are deuterostomes that superimpose radial symmetry upon bilateral larval morphology. Consequently, they are not the first animals that come to mind when the concepts of segmentation and terminal addition are being discussed. However, it has long been recognized that echinoderms have serial elements along their radii formed in accordance with the ocular plate rule (OPR). The OPR is a special case of terminal growth, forming elements of the ambulacra that define the rays in echinoderms. New elements are added at the terminus of the ray, which may or may not be marked by a calcified element called the terminal plate (the "ocular" of sea urchins). The OPR operates in every echinoderm, from the occasionally bizarre fossils of the Cambrian to the most familiar extant taxa. Using the OPR and other criteria of recognition, echinoderm body wall can be divided into two main regions: extraxial components are associated with the somatocoels, axial components (formed in accordance with the OPR) with the hydrocoel. We compare patterns of development in axial regions of echinoderms with those found in the anterior-posterior axes of the earliest echinoderms as well as other invertebrates. Although axial and extraxial skeletons appear to be composed of the same biomineral matrix, the genes involved in patterning these two skeletal components are likely distinct. During development of the axial skeleton, for instance, the genes engrailed and orthodenticle are expressed in spatial and temporal patterns consistent with the OPR. Other genes such as distal-less seem to demarcate early ontogenetic boundaries between the axial rudiment and the extraxial larval body. There is a complex and pervasive reorganization of gene expression domains to produce the highly divergent morphologies seen in the Echinodermata. We integrate morphological and genetic information, particularly with respect to the origins of radial symmetry in the rudiment, and the concomitant development of the rays.

Animals↗
PubMed2005

Abnormal expression of epilepsy-related gene ERG1/NSF in the spontaneous recurrent seizure rats with spatial learning memory deficits induced by kainic acid.

Previous epilepsy-related gene screen identified a spontaneous recurrent seizure (SRS)-related gene named epilepsy-related gene (ERG1) that encodes N-ethylmaleimide-sensitive fusion protein (NSF). To explore whether spatial learning memory deficits are relevant to SRS and whether hippocampal NSF expression is altered by SRS, we used the kainic acid (KA)-induced epilepsy animal model. SRS was monitored for 3 weeks after injection of a single convulsive dose of KA. KA-treated rats with SRS, KA-treated rats without SRS, and saline-treated rats were then measured in Morris water maze. In this spatial learning task, KA-treated rats with SRS performed poorer compared to those without SRS and those treated with saline. During the subsequent probe trials, KA-treated rats with SRS spent less swim path and time in the target quadrant but more swim path and time in the opposite quadrant, and showed fewer platform crossings. Moreover, in situ hybridization and immunohistochemistry showed that both ERG1/NSF mRNA and NSF immunoreactive expression were down-regulated in the CA1 and dorsal dentate gyrus cells (dDGCs) of the hippocampus, and interestingly, tyrosine hydroxylase (TH) immunoreactive dopamine (DA) neurons were lost in ventral tegmental area (VTA) in the KA rats with SRS. These data demonstrate that SRS impairs spatial learning memory and suggest that the down-regulation of NSF expression pattern in the hippocampus and the loss of DA neurons in VTA might contribute to the spatial learning memory deficits induced by SRS.

Animals↗
PubMed1997

Differential expression of the fibroblast growth factor receptor (FGFR) multigene family in normal human adult tissues.

This report describes a systematic analysis of the expression of the fibroblast growth factor receptor (FGFR) multigene family (FGFR1, FGFR2, FGFR3, and FGFR4) in archival serial sections of normal human adult tissues representing the major organ systems, using immunohistochemical techniques. Polyclonal antisera specific for FGFR1, FGFR2, FGFR3, and FGFR4 and a three-stage immunoperoxidase technique were employed to determine the cellular distribution of these receptors at the protein level. The expression profiles for the tissue-specific cellular localization of the FGFR multigene family demonstrated wide-spread and striking differential patterns of expression of individual receptors in the epithelia and mesenchyme of multiple tissues (stomach, salivary glands, pancreas, thymus, ureter, and cornea) and co-expression of FGFR1-4 in the same cell types of other tissues. The wide-spread expression of FGFR1-4 in multiple organ systems suggests an important functional role in normal tissue homeostasis. Differences in the spatial patterns of FGFR gene expression may generate functional diversity in response to FGF-1 and FGF-2, both of which bind with equally high affinity to more than one receptor subtype. In vivo, this may lead to functional differences that are crucial for the regulation of normal physiological processes and are responsible for the pathological mechanisms that orchestrate various disease processes.

Adult↗
PubMed1995

Expression of mef2 genes in the mouse central nervous system suggests a role in neuronal maturation.

Members of the myocyte enhancer factor 2 (MEF2) gene family are expressed in a dynamic pattern during development of the CNS of pre- and postnatal mice. The four MEF2 genes, Mef2A, -B, -C, -D, encode transcription factors belonging to the MADS (MCM1-agamous-deficiens-serum response factor) superfamily of DNA binding proteins. MEF2 factors have previously been shown to be positive regulators of gene expression in terminally differentiated muscle cells. To begin to determine the role of MEF2 factors in CNS development, we used in situ hybridization with gene-specific cRNA probes to define the expression patterns of each of the four Mef2 mRNAs in the developing and mature mouse CNS. Mef2C mRNA was first detected in a ventral portion of the telencephalon at 11.5 d postcoitum (p.c.). By 13.5 d p.c., each of the four Mef2 genes were expressed in overlapping yet distinct patterns in regions of the frontal cortex, midbrain, thalamus, hippocampus, and hindbrain. Temporal and spatial patterns of embryonic Mef2 gene expression appeared to follow gradients of neuron maturation and suggested that the onset of Mef2 gene expression coincides with withdrawal from the cell cycle and initiation of neuronal differentiation. This correlation is particularly striking for Purkinje cells in the cerebellum. Since the molecular mechanisms that regulate neuron differentiation are unknown, we propose that the MEF2 factors are likely to play an important role in this process.

Animals↗
PubMedDate not supplied

Pit-1-dependent expression of the receptor for growth hormone releasing factor mediates pituitary cell growth.

In Snell (dw) and Jackson (dwJ) dwarf mice, mutations in the gene encoding Pit-1, a tissue-specific POU-domain transcription factor, lead to the absence of somatotroph, lactotroph and thyrotroph cells. Pre-somatotroph proliferation is stimulated by increased intracellular levels of cyclic AMP, normally induced by growth hormone releasing factor (GRF; refs 7-17). Here we report the cloning of mouse and rat complementary DNAs encoding a new member of the seven-transmembrane-helix, G-protein-coupled receptor family restricted to the pituitary gland, which mediates increases in intracellular cAMP and cAMP-dependent gene transcription in response to GRF. The receptor is expressed in a spatial and temporal pattern corresponding precisely to growth hormone gene expression, and neither is expressed in dw/dw mice. The pituitary hypoplasia in these mice thus appears to be due, at least in part, to the absence of GRF receptor, which is in turn due to the absence of functional Pit-1.

Amino Acid Sequence↗
PubMed1992

Early mRNAs, spatially restricted along the animal-vegetal axis of sea urchin embryos, include one encoding a protein related to tolloid and BMP-1.

The cloning and characterization of cDNAs representing four genes or small gene families that are coordinately expressed in a spatially restricted pattern during the very early blastula (VEB) stage of sea urchin development are presented. The VEB genes encode multiple transcripts that are expressed transiently in embryos of Strongylocentrotus purpuratus between 16-cell stage and hatching, with peak abundance 12 to 15 hours post-fertilization (approximately 150-250 cells). The VEB transcripts share the same spatial pattern in the early blastula embryo: they are asymmetrically distributed along the animal-vegetal axis but their distribution around this axis is uniform. Thus, the VEB transcripts are the earliest messages to reveal asymmetry along the primary axis in the sea urchin embryo. The temporal and spatial patterns of VEB transcript accumulation are not consistent with involvement of these gene products in cell division or in tissue-specific functions. Furthermore, VEB messages cannot be detected in either ovary or adult tissues, suggesting that these genes function exclusively during embryogenesis. We suggest that the VEB genes function in constructing the early blastula. Two VEB genes encode metalloendoproteases: one (SpHE) is hatching enzyme and the other (SpAN) is similar to bone morphogenetic protein-1 (BMP-1; Wozney et al., Science 242: 1528-1534, 1988) and the Tolloid gene product (tld) (Shimell et al., Cell 67: 459-482, 1991). Several lines of evidence suggest that the VEB genes are regulated directly by factors or regulatory activities localized along the maternally specificed animal-vegetal axis.

Animals↗
PubMed2005

Dual regulation and redundant function of two eye-specific enhancers of the Drosophila retinal determination gene dachshund.

Drosophila eye development is controlled by a conserved network of retinal determination (RD) genes. The RD genes encode nuclear proteins that form complexes and function in concert with extracellular signal-regulated transcription factors. Identification of the genomic regulatory elements that govern the eye-specific expression of the RD genes will allow us to better understand how spatial and temporal control of gene expression occurs during early eye development. We compared conserved non-coding sequences (CNCSs) between five Drosophilids along the approximately 40 kb genomic locus of the RD gene dachshund (dac). Our analysis uncovers two separate eye enhancers in intron eight and the 3' non-coding regions of the dac locus defined by clusters of highly conserved sequences. Loss- and gain-of-function analyses suggest that the 3' eye enhancer is synergistically activated by a combination of eya, so and dpp signaling, and only indirectly activated by ey, whereas the 5' eye enhancer is primarily regulated by ey, acting in concert with eya and so. Disrupting conserved So-binding sites in the 3' eye enhancer prevents reporter expression in vivo. Our results suggest that the two eye enhancers act redundantly and in concert with each other to integrate distinct upstream inputs and direct the eye-specific expression of dac.

3' Untranslated Regions↗
PubMed2001

Neuron-specific expression of Cre recombinase during the late phase of brain development.

Gene targeting to disrupt gene expression in a temporal and spatial manner in a specific tissue using Cre recombinase-mediated gene inactivation has been proven to be useful to study in vivo gene function. To delete genes specifically in neurons during the late phase of brain development, we have generated transgenic mouse lines that express Cre recombinase under the control of the murine neurofilament-H (mNF-H) gene promoter. In this study, we report that one of these mouse lines expresses Cre recombinase specifically in the neurons of the brain and spinal cord during the late stage of their development. The transgenic line displays specific excision of the loxP-flanked gene in the neurons just after embryonic day 18.5 (E.18.5), which coincides with the later phase of brain maturation including spinal cord and olfactory bulb area. This mNF-H-cre transgenic mouse line will be valuable for studying in vivo functions of neuron-specific genes, particularly, defining their precise roles in the mature nervous system using conditional gene targeting strategies.

Age Factors↗
PubMed2004

Does looping and clustering in the nucleus regulate gene expression?

There has been considerable interest in the way that chromatin is spatially organised within the cell nucleus and how that may relate to gene expression and its control. New molecular techniques have identified looped chromatin domains at the mammalian beta-globin and the Drosophila hsp70 loci. Looped domains may insulate chromatin from the influence of neighbouring domains, and the bases of loops may also act to concentrate proteins locally within the nucleus. The spatial clustering of sequences from the Drosophila bithorax complex, located in trans, has also been demonstrated. An emerging theme is that bringing DNA and proteins together within a defined sub-region of the nuclear volume facilitates both the activation and the repression of gene expression. Nuclear compartments may also be involved in the post-translational modification of proteins by sumoylation and ubiquitylation.

Animals↗