Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Genes, Developmental”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,657 records · Page 92Linked to original sources

The molecular and genetic analysis of mouse development.

This review describes some recent advances in the molecular-genetic analysis of mouse development. Reversed genetics and gene assignment have been used to isolate genes affected in developmental mutations. The establishment of a high-density molecular-genetic map promises to facilitate cloning of additional genes with developmental functions. Based on molecular, biochemical or other biological criteria many mouse genes that code for transcriptional regulators, growth-factor-like molecules and their receptors have been isolated. The role of these genes during development can be analysed in vivo after producing targeted mutations. Mutations can be generated by homologous recombination in the genome of embryonic stem cells and can then be introduced into the mouse germ line by means of germ-line chimaeras. Additional approaches employing stem cells to identify and mutate putative developmental genes are coming into use.

Animals↗

A developmental study of novH gene expression in human central nervous system.

The expression pattern of the human nephroblastoma overexpressed (novH) gene in the fetal human central nervous system was examined by in situ hybridization using digoxigenin-labeled novH-specific riboprobes. In the spinal cord, the nov-expressing neurons were first detected both in the ventral region at 16 weeks of gestation (G16W) and in the dorsal region at G38W. In the medulla, nov-expressing neurons were detected in the principal nucleus of the inferior olive, the hypoglossal nucleus and the dorsal motor nucleus of vagus at G16W. Nov-positive neurons were detected at G28W in the nucleus of the spinal tract of the trigeminal and cuneate nucleus, and at G38W in the abducens nucleus of pons, the red nucleus and the substantia nigra of the midbrain, the ventral posterolateral and the mediodorsal thalamic nucleus. A strong labeling was also detected in the striatum of the cerebrum and the cerebral cortex of the parietal lobe. These data established that novH is mainly expressed in somato-motor neurons in the lower central nervous system at early developmental stages and in the higher central nervous system at later stages, suggesting that nov may play an important role in neuronal differentiation.

Central Nervous System↗

Dscr1, a novel endogenous inhibitor of calcineurin signaling, is expressed in the primitive ventricle of the heart and during neurogenesis.

We have demonstrated that DSCR1 acts as a negative regulator of calcineurin-mediated signaling and that its transcript is overexpressed in the Down syndrome (DS) fetal brain. To evaluate the possible involvement of DSCR1 in DS, we have cloned the mouse gene and analyzed its expression pattern in the central nervous system (CNS). Early expression of Dscr1 is detected mainly in the heart tube and in the CNS in rhombomere 4 and the pretectum. From embryonic day 14.5 onwards, Dscr1 is widely distributed in the CNS but becomes more restricted as the brain matures. We confirmed its neuronal expression pattern in the adult, preferentially in Purkinje and pyramidal cells, by double labeling with glial fibrillary acidic protein. We also show that although Dscr1 is present in trisomy in the Ts65Dn mouse, the adult brain expression pattern is not significantly altered. This expression pattern indicated that Dscr1 is a developmentally regulated gene involved in neurogenesis and cardiogenesis and suggests that it may contribute to the alterations observed in these organ systems in DS patients.

Animals↗

Homology and homoplasy: the retention of genetic programmes.

Homology describes the inevitable evolutionary phenomenon that the similarity of structures among different organisms is due to the commonality of their descent. This continuity of information is maintained in evolutionary lineages in terms of genes and developmental mechanisms and will retain 'sameness' and retard, funnel and direct evolutionary diversification. Analogous 'sameness' is said to be due to independent, convergent evolution, and also involves similarity of function; the latter is not a necessary condition for structures to be identified as homologous. Here, I suggest that the biological basis for these seemingly disparate kinds of 'sameness' in evolution may in some, or even most, instances not be all that different and may be based on the same principle-the long evolutionary retention of genes, gene interactions and developmental mechanisms. Evolution might recycle and re-recruit similar mechanisms repeatedly during its course, and it often makes do with what is already available to it rather than to newly evolve or reinvent many gene interactions and developmental mechanisms repeatedly. Apparently there is no, or only a negligible, 'genomic cost' or even a selective advantage to maintaining genes and developmental mechanisms for long evolutionary periods of time, even if they are not continuously used in all members along an evolutionary line. Therefore, the biological basis of both homologous traits (those that are evolutionarily always expressed) and homoplasious traits (those that are not always 'on', but are 're-awakened' during evolution) might not be so different, and the distinction between homology and some forms of homoplasy may be somewhat artificial.

Amphibians↗

Drosophila Lyra mutations are gain-of-function mutations of senseless.

The Lyra mutation was first described by Jerry Coyne in 1935. Lyra causes recessive pupal lethality and adult heterozygous Lyra mutants exhibit a dominant loss of the anterior and posterior wing margins. Unlike many mutations that cause loss of wing tissue (e.g., scalloped, Beadex, cut, and apterous-Xasta), Lyra wing discs do not exhibit increased necrotic or apoptotic cell death, nor do they show altered BrdU incorporation. However, during wing disc eversion, loss of the anterior and posterior wing margins is apparent. We have previously shown that senseless, a gene that is necessary and sufficient for peripheral nervous system (PNS) development, is allelic to Lyra. Here we show by several genetic criteria that Lyra alleles are neomorphic alleles of senseless that cause ectopic expression of SENSELESS in the wing pouch. Similarly, overexpression of SENSELESS in the wing disc causes loss of wing margin tissue, thereby mimicking the Lyra phenotype. Lyra mutants display aberrant expression of DELTA, VESTIGIAL, WINGLESS, and CUT. As in Lyra mutants, overexpression of SENSELESS in some areas of the wing pouch also leads to loss of WINGLESS and CUT. In summary, our data indicate that overexpression of SENSELESS causes a severe reduction in NOTCH signaling that in turn may lead to decreased transcription of several key genes required for wing development, leading to a failure in cell proliferation and loss of wing margin tissue.

Alleles↗

Comparative developmental genetics and the evolution of arthropod body plans.

The arthropods display a wide range of morphological diversity, varying tagmosis, as well as other aspects of the body plan, such as appendage and cuticular morphology. Here we review the roles of developmental regulatory genes in the evolution of arthropod morphology, with an emphasis on what is known from morphologically diverse species. Examination of tagmatic evolution reveals that these changes have been accompanied by changes in the expression patterns of Hox genes. In contrast, review of the modifications to wing morphology seen in insects shows that these body plan changes have generally favored alterations in downstream target genes. These and other examples are used to discuss the evolutionary implications of comparative developmental genetic data.

Animals↗

Identification of Eimeria bovis merozoite cDNAs using differential mRNA display.

Differences in gene expression between Eimeria bovis sporozoites and first-generation merozoites were analyzed using the technique of differential mRNA display. Approx. 5% of the sequences detected in first-generation merozoites appear to be unique relative to sporozoites. Several of the bands corresponding to merozoite-specific gene expression were isolated and cloned. Northern blot analysis revealed that the cDNA fragments DMZ-7, DMZ-8 and NMZ-6 hybridized to mRNAs expressed at > 50-fold higher levels in merozoites relative to sporozoites. A fourth cDNA fragment, NMZ-4, hybridized to a mRNA expressed at 3-fold higher levels in merozoites. Further characterization demonstrated that expression of DMZ-8 in E. bovis-infected bovine cells begins as early as 12 h after sporozoite invasion and continues throughout the entire 14 days of first-generation schizogony. Sequence analysis of each of the four merozoite cDNAs failed to identify any significant similarity to any entries in the GenBank database, suggesting that these developmentally regulated genes may be unique to coccidian parasites.

Animals↗

Expression of the cartilage matrix protein gene at different chondrocyte developmental stages.

Cartilage matrix protein (CMP), a major noncollagenous component of certain types of hyaline cartilage, is synthesized by chondrocytes in a developmentally regulated manner. In this study, we monitored the accumulation of CMP in the developing chicken limb and sternum by immunostaining. In older embryos, the specific extracellular staining was restricted to the resting/proliferative zone of metaphyseal cartilage and to the immediately adjacent hypertrophic cartilage. A lack of staining was observed in the peripheral layers of articular cartilage. Data were compared with the accumulation of CMP mRNA measured by Northern analysis relative to other cartilage-specific messages in cell cultures representing different stages of chondrocyte differentiation, as well as with the steady state mRNA levels in tissue samples. We found a correlation between the gene expression pattern of the in vitro cultures and the one observed in certain in vivo differentiation stages. The high-density mesenchyme culture was utilized as a model for studying the events at early stage I (stage Ia) of chondrogenesis. This culture was characterized by relatively low steady state mRNA levels for cartilage proteins, including the later activation of the CMP gene as compared to type II collagen or link protein genes, and relatively high steady state mRNA levels for type VI collagen and beta-actin. Chicken embryo chondrocyte cultures obtained from sterna of 14-day-old embryos, however, consisted predominantly of stage Ib chondrocytes, and showed high steady state levels for cartilage proteins, but relatively lower levels for type VI collagen and beta-actin mRNAs. In accordance with the in vivo data, a relatively high steady state level was detected for CMP mRNA in cultures of hypertrophic (stage II) chondrocytes. We also performed transient expression assays in the various culture systems to study the role of the promoter upstream and intronic control regions in the tissue- and developmental stage-specific regulation of the CMP gene. We showed that the enhancer worked in a lineage-specific manner, by further stimulating the minimal promoter activity independent of the developmental stage of chondrocytes, while it did not in other tissues. The promoter upstream control regions, however, seemed to play a role in restricting the promoter activity to a certain chondrocyte developmental stage.

Animals↗

Modulation of expression at the level of splicing of cut-1 RNA in the infective second-stage juvenile of the plant parasitic nematode Meloidogyne artiellia.

The cut-1 gene coding for cuticlin-1 has been isolated from the plant parasitic nematode Meloidogyne artiellia. The sequence of the cut-1 gene was compared with the corresponding sequence from the free-living nematode Caenorhabditis elegans. The high degree of similarity between the amino acid sequences, together with the occurrence of characteristic sequence motifs, indicates that the cuticlin-1 is a non-collagenous component of the cuticle also in plant parasitic nematodes. Studies on the expression pattern during the development of M. artiellia indicate that there is a burst of expression of this gene during moulting. Then, the expression rate is reduced in the infective juveniles, which migrate in the soil. In the sedentary females, in contrast, no expression is detected, while in the males which move freely through the soil, the gene is expressed and the transcript fully processed. These data strongly suggest that the gene is developmentally regulated. It is proposed that the production of cuticlin plays an important role in determining the mechanical properties of the cuticle. Furthermore, evidence is provided to indicate that the modulation of cut-1 expression is achieved by regulation of the cis-splicing mechanism in the infective second-stage juvenile.

Amino Acid Sequence↗

Two novel MYB homologues with changed expression in late embryogenesis-defective Arabidopsis mutants.

Two novel MYB genes (ATMYBR1 and ATMYBR2) were isolated from Arabidopsis thaliana. Binding to a conserved MYB recognition sequence is demonstrated for the ATMYBR1 protein. The expression of both genes is affected by the fus3, lec1 and abi3 mutations causing pleiotropic defects during late embryogenesis and seed maturation including the loss of dormancy and desiccation tolerance. The strong increase of the transcript levels of both MYB genes during very late stages of embryogenesis typically found in wild type is missing in the mutants. Furthermore, the expression of both MYB genes is developmentally regulated in vegetative tissues. The highly conserved repeats (R2 and R3) of the DNA binding MYB domain of both proteins represent chimeric structures combining features typical of plant and animal derived proteins. This demonstrates the existence of a distinct subfamily of animal-like MYB factors in plant genomes.

Amino Acid Sequence↗

Pem homeobox gene promoter sequences that direct transcription in a Sertoli cell-specific, stage-specific, and androgen-dependent manner in the testis in vivo.

Although many genes are expressed selectively in Sertoli cells, regulatory sequences sufficient to drive Sertoli cell-specific expression in the postnatal and adult testis in vivo have not been identified. In the present study, we identified promoter sequences from the Pem homeobox gene that direct Sertoli cell-specific expression in an androgen-dependent and stage-specific manner. Immunohistochemical and RNA analysis demonstrated that 0.6-kb 5'-flanking sequence directed transgene expression specifically in the testis and the epididymis but not in any other tissues tested. In the adult testis, this promoter fragment targeted the transgene expression specifically to Sertoli cells during stages IV-VIII of the seminiferous epithelial cycle, thereby mimicking the expression pattern of the endogenous Pem gene. This promoter fragment also recapitulated Pem's normal postnatal expression pattern, as it directed transcript induction between d 6 and d 9 post partum. Deletion of 0.3 kb from the 5'-end of the transgene had no effect on androgen-dependent Sertoli-specific expression but altered stage-specific expression in adult testes and caused premature postnatal expression. Our results suggest that there are at least two regulatory regions in the Pem proximal promoter: one that directs androgen receptor-dependent expression specifically in Sertoli cells within the testis and another that confers stage-specific expression in neonates and adults by acting as a negative regulator. To our knowledge, this is the first identification of regulatory regions that direct faithful developmentally regulated gene expression in postnatal and adult Sertoli cells in vivo.

5' Flanking Region↗

Developmental and inducible accumulation of gene transcripts involved in alkaloid biosynthesis in opium poppy.

Opium poppy (Papaver somniferum) produces a large number of benzylisoquinoline alkaloids, including morphine and sanguinarine, derived from tyrosine via the branch-point intermediate (S)-reticuline. Molecular clones for the three methlytransferases involved in (S)-reticuline biosynthesis, (S)-norcoclaurine-6-O-methyltransferase (6OMT), (S)-3'-hydroxy-N-methylcoclaurine-4'-O-methyltransferase (4'OMT), and (S)-coclaurine N-methyltransferase (CNMT), were isolated from opium poppy and shown to share extensive homology with the corresponding cDNAs from Japanese goldthread (Coptis japonica). These cDNAs were used together with previously isolated clones for tyrosine/dopa decarboxylase (TYDC), (S)-N-methylcoclaurine-3'-hydroxylase (CYP80B1), berberine bridge enzyme, (BBE), (7S)-salutaridinol 7-O-acetyltransferase (SAT), and codeinone reductase (COR), to compare the accumulation of gene transcripts encoding eight alkaloid biosynthetic enzymes in opium poppy. Transcript levels generally increased in developing seedlings and were consistently high in stems and flower buds, but were more variable in roots and leaves of mature plants. The accumulation of each transcript, with the exception of COR, showed a marked induction in response to elicitor treatment or wounding of cultured cells. Specific gene transcript levels often correlated with the accumulation of morphine or sanguinarine, with notable exceptions. Our data suggest some degree of coordination in the developmental and inducible regulation of alkaloid biosynthetic genes in opium poppy.

Alkaloids↗

Glycine-rich protein genes, which encode a major component of the cuticle, have different developmental profiles from other cuticle protein genes in Bombyx mori.

Three types of GRP (glycine-rich proteins) cDNAs were identified in the EST database of Bombyx mori. These came from 21 ESTs in the W3-stage wing disc EST library. We named them BmGRP1, BmGRP2 and BmGRP3. BmGRP1 and BmGRP2 had 57% identity in deduced amino acid sequences. Expression of all BmGRPs was observed in the epidermis at the fourth molting stage, and in the wing at pupation and mid-pupal stage. It is suggested that BmGRPs contribute to larval, pupal and adult cuticles together with other cuticle proteins. Transcripts of BmGRP2 increased after 7 days of pupal stage. BmGRP2 is suggested to construct adult trachea in the wing. Hormonal response of BmGRPs was compared with that of another group of cuticular protein genes, BMWCPs. BmGRPs were induced by a pulse of 20E. Induction of BmGRP3 was observed in W1 wing discs in the presence of JHA which was added with 20E, whereas that of BMWCP2 was inhibited in the presence of JHA. Induction of BmGRPs was observed in the wing discs of V3 and W1 stages, while that of BMWCP2 was not observed in the V3 wing discs. These differences between BMWCPs and BmGRPs in response to hormones at different developmental stages are discussed.

Amino Acid Sequence↗

Wnt gene expression in sea urchin development: heterochronies associated with the evolution of developmental mode.

The Wnt genes encode a large family of conserved secreted proteins that are widely involved in animal development. The variety and ubiquity of this ancient family suggest that Wnt genes may have been important in the evolution of animal development, including early development. To test this hypothesis, we have characterized the expression of several Wnt genes in closely related sea urchins that exhibit radically different modes of early development. Wnt-1, -4, and -5 genes exhibit several conserved molecular and developmental characteristics, both within sea urchins and with Wnt genes examined in other animals (Ferkowicz et al. 1998). Here, we demonstrate that sea urchin Wnt-5 transcripts are specifically detected by in situ hybridization in discrete embryonic, larval, and developing adult tissues and processes: (1) in a band of vegetal ectoderm in mesenchyme blastula stage embryos, (2) in the larval ciliary bands, (3) in tissues that form the early adult rudiment (left coelomic pouch and overlying vestibular ectoderm), and (4) in the developing adult radial nervous system. We find that the sites of Wnt-5 transcript accumulation are conserved in species exhibiting either indirect- or direct-developmental modes, suggesting that Wnt-5 function(s) have been conserved in sea urchin development. However, dramatic heterochronic changes in Wnt-5 gene expression have occurred in the direct-developing species that parallel the accelerated morphological changes that occur during direct development. These results suggest that heterochronic changes in the expression of conserved developmental regulatory genes, such as the Wnt family members, are agents of evolutionary change in animal development.

Animals↗

Comparative EST analyses provide insights into gene expression in two asexual developmental stages of Eimeria tenella.

The protozoan parasite Eimeria tenella has a complex life cycle that includes two major asexual developmental stages, the merozoite and the sporozoite. The expressed sequence tag (EST) approach has been previously used to study gene expression of merozoites. We report here the generation and analysis of 556 ESTs from sporozoites. Comparative analyses of the two datasets reveal a number of transcripts that are preferentially expressed in a specific stage, including previously uncharacterised sequences. The data presented indicate the invaluable potential of the comparative EST analysis for providing information on gene expression patterns in the different developmental stages of E. tenella.

Animals↗

Sonic Hedgehog, a key development gene, experienced intensified molecular evolution in primates.

Sonic Hedgehog (SHH) is one of the most intensively studied genes in developmental biology. It is a highly conserved gene, found in species as diverse as arthropods and mammals. The mammalian SHH encodes a signaling molecule that plays a central role in developmental patterning, especially of the nervous system and the skeletal system. Here, we show that the molecular evolution of SHH is markedly accelerated in primates relative to other mammals. We further show that within primates, the acceleration is most prominent along the lineage leading to humans. Finally, we show that the acceleration in the lineage leading to humans is coupled with signatures of adaptive evolution. In particular, the lineage leading to humans is characterized by a rampant and statistically highly non-random gain of serines and threonines, residues that are potential substrates of post-translational modifications. This suggests that SHH might have evolved more complex post-translational regulation in the lineage leading to humans. Collectively, these findings implicate SHH as a potential contributor to the evolution of primate- or human-specific morphological traits in the nervous and/or skeletal systems and provide the impetus for additional studies aimed at identifying the primate- or human-specific functions of this key development gene.

Animals↗

An AP1 binding site upstream of the kappa immunoglobulin intron enhancer binds inducible factors and contributes to expression.

Expression of the kappa immunoglobulin light chain gene requires developmental- and tissue-specific regulation by trans-acting factors which interact with two distinct enhancer elements. A new protein-DNA interaction has been identified upstream of the intron enhancer, within the matrix-associated region of the J-C intron. The binding activity is greatly inducible in pre-B cells by bacterial lipopolysaccharide and interleukin-1 but specific complexes are found at all stages of B cell development tested. The footprinted binding site is homologous to the consensus AP1 motif. The protein components of this complex are specifically competed by an AP1 consensus motif and were shown by supershift to include c-Jun and c-Fos, suggesting that this binding site is an AP1 motif and that the Jun and Fos families of transcription factors play a role in the regulation of the kappa light chain gene. Mutation of the AP1 motif in the context of the intron enhancer was shown to decrease enhancer-mediated activation of the promoter in both pre-B cells induced with LPS and constitutive expression in mature B cells.

Animals↗

A variable cluster of ethylene response factor-like genes regulates metabolic and developmental acclimation responses to submergence in rice.

Submergence-1 (Sub1), a major quantitative trait locus affecting tolerance to complete submergence in lowland rice (Oryza sativa), contains two or three ethylene response factor (ERF)-like genes whose transcripts are regulated by submergence. In the submergence-intolerant japonica cultivar M202, this locus encodes two ERF genes, Sub1B and Sub1C. In the tolerant near-isogenic line containing the Sub1 locus from the indica FR13A, M202(Sub1), the locus additionally encodes the ERF gene Sub1A. During submergence, the tolerant M202(Sub1) displayed restrained leaf and internode elongation, chlorophyll degradation, and carbohydrate consumption, whereas the enzymatic activities of pyruvate decarboxylase and alcohol dehydrogenase were increased significantly compared with the intolerant M202. Transcript levels of genes associated with carbohydrate consumption, ethanolic fermentation, and cell expansion were distinctly regulated in the two lines. Sub1A and Sub1C transcript levels were shown to be upregulated by submergence and ethylene, with the Sub1C allele in M202 also upregulated by treatment with gibberellic acid (GA). These findings demonstrate that the Sub1 region haplotype determines ethylene- and GA-mediated metabolic and developmental responses to submergence through differential expression of Sub1A and Sub1C. Submergence tolerance in lowland rice is conferred by a specific allele variant of Sub1A that dampens ethylene production and GA responsiveness, causing quiescence in growth that correlates with the capacity for regrowth upon desubmergence.

Acclimatization↗