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 1,567 records · Page 87Linked to original sources

Developmental expression and modification of genes.

Differentiating tissue is characterized by a specific repertoire of proteins out of which some are developmentally controlled. This review describes modifications in the structure of genes which encode developmentally regulated proteins. Evidence is provided for changes in chromatin conformation and DNA methylation of specific genes-either change can be observed in various stages of some vertebrates. The involvement of hormones in regulating DNA modifications is suggested, and interrelationships between DNA modifications and gene expression are discussed.

5-Methylcytosine↗

Developmental expression of the murine Mobp gene.

In this report we describe the developmental expression of the murine (Mobp) gene encoding myelin-associated oligodendrocytic basic protein. We have characterized three Mobp cDNA clones which have been used as probes. Murine Mobp splice variant-1 (mmsv-1), a portion of 3' untranslated region (UTR), is homologous to 3' UTR sequences found in the rat Mobp splice variants rOP1, Mobp81-A and Mobp-99. The mmsv-2 sequence, encoding 81 amino acids, closely resembles the rat Mobp81-A splice variant. The mmsv-3 cDNA, encoding 170 amino acids corresponding closely to the rat rOPRP1 splice variant, detects a single mRNA species present in low levels from E12 onward, suggesting this MOBP may have a function alternative or additional to involvement in myelin formation. The mmsv-1 probe detects an mRNA species abundantly expressed in the postnatal central nervous system (CNS) but barely detectable at E18. This mRNA is located initially in the cell bodies of oligodendrocytes, moving distally into their processes as myelination proceeds. The most abundant mmsv(s) in the adult CNS are present at detectable levels after expression of the myelin basic protein (Mbp) gene and marginally after or coincident with the proteolipid protein (Plp) gene. The level of the abundant, late-expressed mRNA correlates closely with the capacity to form myelin and the maturity of oligodendrocytes, as shown in two hypomyelinated mutants, rumpshaker and jimpy, which represent mildly and severely affected phenotypes, respectively.

Animals↗

Microarray gene expression profiling of developmental transitions in Sitka spruce (Picea sitchensis) apical shoots.

The apical shoot drives the yearly new stem growth of conifer trees, is the primary site for the establishment of chemical and physical defences, and is important in establishing subsequent perennial growth. This organ presents an interesting developmental system, with growth and development progressing from a meristematic tip through development of a primary vascular system, to a base with fully differentiated and lignified secondary xylem on the inside and bark tissue with constitutive defence structures such as resin, polyphenolic phloem parenchyma cells, and sclereids on the outside. A spruce (Picea spp.) microarray containing approximately 16.7K unique cDNAs was used to study transcript profiles that characterize the developmental transition in apical shoots of Sitka spruce (Picea sitchensis) from their vegetative tips to their woody bases. Along with genes involved in cell-wall modification and lignin biosynthesis, a number of differentially regulated genes encoding protein kinases and transcription factors with base-preferred expression patterns were identified, which could play roles in the formation of woody tissues inside the apical shoot, as well as in regulating other developmental transitions associated with organ maturation. Preferential expression of known conifer defence genes, genes encoding defence-related proteins, and genes encoding regulatory proteins was observed at the apical shoot tip and in the green bark tissues at the apical shoot base, suggesting a commitment to constitutive defence in the apical shoot that is co-ordinated with rapid development of secondary xylem.

Antigens, Plant↗

Homeobox gene expression in cancer: insights from developmental regulation and deregulation.

Homeobox genes encode transcription factors that play essential roles in controlling cell growth and differentiation during embryonic development. Many homeobox genes are aberrantly expressed in a wide variety of solid tumours, and their deregulation appears to enhance cell survival and proliferation and to inhibit differentiation. In hematologic malignancies, deregulated homeobox genes profoundly perturb self-renewal and proliferation of hematopoietic stem cells and progenitors. It is increasingly recognised that solid tumours, like hematologic malignancies, could arise from cancer stem cells, and that targeting these cells could be the most effective means of inhibiting tumour progression and disease recurrence. Studying the biological effects and mechanisms of homeobox genes in cancers could provide valuable insights into identifying cancer stem cells and targeting the self-renewal pathways in these cell populations.

Cell Transformation, Neoplastic↗

Molecular characterization of a developmentally regulated porcine skeletal myosin heavy chain gene and its 5' regulatory region.

Members of the myosin heavy chain (MyHC) gene family show developmental stage- and spatial-specificity of expression. We report on the characterization and identification of a porcine skeletal fast MyHC gene, including its corresponding 5' end cDNA and 5' regulatory region. This MyHC isoform was found exclusively in skeletal muscles from about the last quarter of gestation through to adulthood. Expression of this isoform was higher postnatally and its spatial distribution resembled a rosette cluster; each with a ring of fast fibres surrounding a central slow fibre. This rosette pattern was absent in the adult diaphragm but about 20% of the fibres continued to express this MyHC isoform. Further in vivo expression studies, in a variety of morphologically and functionally diverse muscles, showed that this particular skeletal MyHC isoform was expressed in fast oxidative-glycolytic fibres, suggesting that it was the equivalent of the fast IIA isoform. Two domains in the upstream regulatory region were found to confer differentiation-specific expression on C2 myotubes (-1007 to -828 and -455 to -101), based on in vitro transient expression assays using the chloramphenicol acetyltransferase (CAT) reporter gene. Interestingly, for high levels of CAT expression to occur, a 3' region, extending from the transcriptional start site to part. of intron 2, must be present in all the DNA constructs used.

Aging↗

Expression of Dlx and Lhx family homeobox genes in fetal thymus and thymocytes.

Homeobox genes comprise a nearly ubiquitous and highly conserved superfamily of developmental regulatory genes that encode transcription factors involved in the determination of axis and tissue identity. While homeobox gene expression has been well characterized in a variety of embryonic tissues, their expression has not been extensively studied in lymphoid progenitor cells or in sites of lymphogenesis. To examine homeobox gene expression in the developing thymus, we screened an embryonic day 13.5 thymus cDNA library by polymerase chain reaction (PCR) using degenerate oligonucleotides within the highly conserved homeodomain region of eight homeobox gene families. The resulting PCR products were then cloned and sequenced. Transcripts for multiple Dlx family members and Lhx2 were repeatedly detected in this screen. Screening of embryonic day 16.5 and adult murine thymus and Thy1+ thymocytes was performed for selected members of these homeobox gene families. Transcripts encoding Lhx2, Lhx3, and Lhx9, as well as Dlx1 and Dlx2 were detected in both thymus and purified thymocytes. Dlx1 is a member of the distal-less homeobox gene family that has been shown to regulate embryonic craniofacial development. Significantly, Dlx1 is expressed in the third branchial arch, which contributes to the thymus. Although Dlx1 knockout mice did not display any obvious developmental defects in thymus or thymocyte development, the expression of these homeobox genes in neural crest derivatives suggests a possible role in cell migration and development that may overlap with other homeobox genes.

Animals↗

Developmental regulation of angiotensinogen gene expression in sheep.

It has been suggested that the liver is not the main source of angiotensinogen during fetal life in rats, but that the kidney is an important site of fetal angiotensinogen synthesis. In an effort to determine if this phenomenon is specific to the rat or applicable to other species, we compared the ontogenic changes in hepatic and renal angiotensinogen mRNA expression in fetal (60, 90, 118, and 138 d of gestation, term being 145 d), newborn (7 d postnatal), and adult sheep. Total RNA was extracted, subjected to Northern blotting and hybridized using a full-length rat radiolabeled antisense RNA. Angiotensinogen mRNA sequences were detected in all fetal liver samples and appeared to increase 3-fold from 60 to 138 d gestation and then to decrease after birth. In contrast, angiotensinogen mRNA could not be detected in renal cortical tissue of 118 or 138 d fetuses, or newborn or adult sheep. We conclude that, unlike in the rat, liver angiotensinogen gene expression is detectable during the 2nd trimester of gestation in sheep and is developmentally regulated. Furthermore, in contrast to the fetal rat, angiotensinogen mRNA sequences were undetectable in fetal sheep kidney.

Angiotensinogen↗

Crossroads, milestones and landmarks in insect development and evolution: implications for systematics.

Our understanding of insect development and evolution has increased greatly due to recent advances in the comparative developmental approach. Modern developmental biology techniques such as in situ hybridization and molecular analysis of developmentally important genes and gene families have greatly facilitated these advances. The role of the comparative developmental approach in insect systematics is explored in this paper and we suggest two important applications of the approach to insect systematics--character dissection and morphological landmarking. Existing morphological characters can be dissected into their genetic and molecular components in some cases and this will lead to more and richer character information in systematic studies. Character landmarking will he essential to systematic studies for clarifying structures such as shapes or convergences, which are previously hard to analyze anatomical regions. Both approaches will aid greatly in expanding our understanding of homology in particular, and insect development in general.

Animals↗

Preliminary evidence of phenytoin-induced alterations in embryonic gene expression in a mouse model.

SWV mouse embryos collected on gestational days (GD) 9:12 and 10:00 following chronic in utero exposure to teratogenic concentrations of phenytoin were utilized for in situ transcription studies of gene expression. The substrate cDNA obtained from the frozen embryo sections was amplified into radiolabelled antisense RNA (RT/aRNA) and used as a probe to screen a panel of 20 cDNA clones representing genes that are important regulators of craniofacial and neural development. The magnitude of alteration in gene expression following phenytoin treatment was determined densitometrically by changes in the hybridization intensity of the aRNA probes to the cDNA clones immobilized to the slot blots. We found that both Wnt-1 and the calcium channel gene were developmentally regulated, as their level of expression decreased significantly between the two collection times. Phenytoin treatment produced a significant downregulation in the level of expression for 25% of the genes examined in the GD 9:12 embryos, including the growth factors TGF-beta and NT3, the proto-oncogene Wnt-1, the nicotinic receptor, and the voltage sensitive calcium channel gene. Additional changes in the coordinate expression of several of the growth and transcription factors were observed at both gestational timepoints. The application of RT/aRNA technology has extended our appreciation of the normal patterns of gene expression during craniofacial and neural development, and provided the first demonstration of multiple coordinate changes in transcription patterns following teratogenic insult.

Analysis of Variance↗

CYP76C2, an Arabidopsis thaliana cytochrome P450 gene expressed during hypersensitive and developmental cell death.

The characterisation of an Arabidopsis thaliana cytochrome P450-encoding cDNA clone, B72, preferentially expressed during the hypersensitive response (HR) provoked by the bacterial pathogen Pseudomonas syringae pathovar maculicola, is reported. The B72 cDNA clone corresponded to the CYP76C2 gene, which belongs to a small multigene family comprising four genes. HR-triggering bacteria harbouring different avirulence genes induced the accumulation of transcripts of this P450 gene. CYP76C2 gene expression was moreover associated with various processes leading to cell death such as leaf senescence, ageing of cell cultures, wounding as well as with treatment with the necrotising heavy metal salt, lead nitrate.

Arabidopsis↗

Analysis of two transcription activation elements in the promoter of the developmentally regulated con-10 gene of Neurospora crassa.

The con-10 gene of Neurospora crassa is activated during conidiation. CRS-B (conidiation response sequence-B) and CGE (con-10 general enhancer) elements have been proposed to function as sites of transcriptional activation and as possible elements that confer developmental regulation to con-10. In a specific analysis of the roles of these elements we found that two CRS-B elements are necessary for full activation of con-10 during macroconidiation, whereas two CGE elements are functionally redundant, such that a single CGE is sufficient for maximal expression. However, CRS-B and CGE elements are not sufficient for developmental activation of a reporter gene. The CRS-B element was further dissected and one of the CRS-B elements appears to function in repression as well as activation. con-10 is also highly expressed during microconidiation, a different form of asexual sporulation, but we show here that CRS-B elements do not play a significant role in con-10 expression during microconidiation. Both CRS-B elements contribute to basal con-10 expression during mycelial growth. con-10 is also regulated by light, and CRS-B and CGE elements may play minor roles in controlling con-10 expression in response to light.

Base Sequence↗

Production of chimaeric mice containing embryonic stem (ES) cells carrying a homoeobox Hox 1.1 allele mutated by homologous recombination.

Several mouse gene families related to Drosophila developmental control genes and containing a homoeobox, a paired box or a finger domain, have been cloned and structurally analysed. On the basis of structural similarities to the Drosophila genes and of their spatially and temporally restricted expression patterns during mouse embryogenesis, it has been proposed that these mammalian genes also are involved in the control of development. To elucidate the function of homoeobox genes by genetic means, mouse mutants must be generated. We have developed a technique for mutagenesis in vivo and have used it to mutate the homoeobox Hox 1.1 gene. In vivo mutagenesis was achieved through homologous recombination between an endogenous Hox 1.1 allele and a microinjected mutated gene in pluripotent embryonic stem (ES) cells. Mutant cells were identified by means of the polymerase chain reaction (PCR) and mutant clones were used to generate chimaeric mice. Because the homologous recombination event is formally a gene conversion event and no selection is required to screen for cells carrying the mutated allele, in vivo mutagenesis allows specific alterations in the target sequence to be made without the introduction of any other sequences.

Animals↗

Human heavy-chain variable region gene family nonrandomly rearranged in familial chronic lymphocytic leukemia.

We have identified a family of human immunoglobulin heavy-chain variable-region (VH) genes, one member of which is rearranged in two affected members of a family in which the father and four of five siblings developed chronic lymphocytic leukemia. Cloning and sequencing of the rearranged VH genes from leukemic lymphocytes of three affected siblings showed that two siblings had rearranged VH genes (VHTS1 and VHWS1) that were 90% homologous. The corresponding germ-line gene, VH251, was found to be part of a small (four gene) VH gene family, which we term VHV. The DNA sequence homology to VHWS1 (95%) and VHTS1 (88%) and identical restriction sites on the 5' side of VH confirm that rearrangement of VH251 followed by somatic mutation produced the identical VH gene rearrangements in the two siblings. VHTS1 is not a functional VH gene; a functional VH rearrangement was found on the other chromosome of this patient. The other two siblings had different VH gene rearrangements. All used different diversity genes. Mechanisms proposed for non-random selection of a single VH gene include developmental regulation of this VH gene rearrangement or selection of a subpopulation of B cells in which this VH has been rearranged.

Amino Acid Sequence↗

Molecular cloning of an olfactory gene from Drosophila melanogaster.

An olfactory gene olfE, which affects response to benzaldehyde in larvae and adults of Drosophila melanogaster, has been mapped between two breakpoints on the X chromosome. The breakpoints have been shown to lie at a distance no greater than 25 kilobases (kb). A 14-kb genomic fragment from this region has been used for germ-line transformation of olfE mutant flies, and in one of three transformant lines obtained, rescue of the olfE phenotype is observed by two separate behavioral assays. Transcript analysis of the region that rescues the olfE phenotype has shown one major transcript at 5.4 kb and a minor one at 1.7 kb. Both of these transcripts are probably alternatively spliced products of the olfE gene. A developmental and tissue-specific profile of the 5.4-kb olfE message has shown that it is present at all developmental stages, suggesting that the gene may be multifunctional.

Animals↗

Organization, expression and evolution of a disease resistance gene cluster in soybean.

PCR amplification was previously used to identify a cluster of resistance gene analogues (RGAs) on soybean linkage group J. Resistance to powdery mildew (Rmd-c), Phytophthora stem and root rot (Rps2), and an ineffective nodulation gene (Rj2) map within this cluster. BAC fingerprinting and RGA-specific primers were used to develop a contig of BAC clones spanning this region in cultivar "Williams 82" [rps2, Rmd (adult onset), rj2]. Two cDNAs with homology to the TIR/NBD/LRR family of R-genes have also been mapped to opposite ends of a BAC in the contig Gm_Isb001_091F11 (BAC 91F11). Sequence analyses of BAC 91F11 identified 16 different resistance-like gene (RLG) sequences with homology to the TIR/NBD/LRR family of disease resistance genes. Four of these RLGs represent two potentially novel classes of disease resistance genes: TIR/NBD domains fused inframe to a putative defense-related protein (NtPRp27-like) and TIR domains fused inframe to soybean calmodulin Ca(2+)-binding domains. RT-PCR analyses using gene-specific primers allowed us to monitor the expression of individual genes in different tissues and developmental stages. Three genes appeared to be constitutively expressed, while three were differentially expressed. Analyses of the R-genes within this BAC suggest that R-gene evolution in soybean is a complex and dynamic process.

Amino Acid Sequence↗

Regulation of laccase biosynthesis in the plant-pathogenic fungus Cryphonectria parasitica by double-stranded RNA.

Transmissible hypovirulence of the chestnut blight fungus, Cryphonectria parasitica, is associated with cytoplasmic double-stranded-RNA (dsRNA) viruses. The fungal laccase has attracted interest because its activity is reduced in hypovirulent dsRNA-containing strains. A laccase cDNA clone was isolated by screening a cDNA expression library with antibodies against the purified extracellular laccase. The amino acid sequence deduced from part of the cDNA clone revealed high homology to other fungal laccases, especially to the Neurospora crassa laccase. A major laccase transcript 2.3 kb in length was detected in Northern (RNA) blots. In liquid culture, extracellular laccase activity was reduced by about 75% in the hypovirulent (dsRNA-free) strain EP155/2. In contrast, production of biomass was not affected by the dsRNA. Northern blot analysis indicated that dsRNA down regulates laccase biosynthesis by reducing laccase mRNA accumulation. The laccase gene is one of several developmentally regulated genes affected by the presence of dsRNA.

Amino Acid Sequence↗

Evaluation of candidate genes for familial brachydactyly.

Type A1 brachydactyly in humans is a recognisable syndrome characterised by shortening of the middle phalanx of all digits with occasional fusion of the middle and terminal phalanges. The purpose of this study was to evaluate candidate genes for type A1 brachydactyly in two families with multiple affected members. Several classes of genes have been implicated in the control of distal limb development including homeobox containing genes (MSX1, MSX2) some members of the homeobox gene family, and genes encoding growth factors of the FGF, TGF, and PDGF families. Homeobox (Hox) genes are a family of developmental control genes activated early in embryogenesis that encode positional information along the anterior-posterior body axis and specify distinct spatial domains within developing limbs. Growth factor genes can regulate the proliferation and differentiation of various embryonic structures including limb buds and have been shown to influence Hox gene expression. Candidate genes HOXD, MSX1, MSX2, FGF-1, and FGF-2 were excluded in one family. The brachydactyly type A1 gene or locus was not found in either of the two families studied.

Base Sequence↗

New albumin gene 3' adjacent to the alpha 1-fetoprotein locus.

The albumin multigene family encodes proteins synthesized in the liver and secreted in the serum to fulfill ligand-carrier functions. The albumin (ALB), alpha 1-fetoprotein (AFP), and vitamin D-binding protein genes are syntenic, the ALB and AFP genes are organized in tandem, and the AFP gene is selectively expressed in the fetal liver. We now report the existence of a fourth member of the albumin gene family, located 10 kilobases downstream from the AFP locus. The new gene, named alpha-albumin (alpha ALB), is selectively expressed in the liver at late stages of development. The alpha ALB mRNA sequence encodes a predicted secreted protein with the typical triple domain disulfide cross-linked structure. Comparisons of coding and promoter sequences suggest that alpha ALB could be a phylogenetic intermediate between the ALB and AFP genes. The developmental switch between alpha ALB gene activation and AFP gene repression suggests new regulatory interplays at the albumin locus and adult stage-specific ligand binding functions carried out by the alpha ALB gene product.

Albumins↗