bluuebunny/crossref_metadata_2025_split huggingface dataset:
Murine “housekeeping” enzyme (genetic locus:Idh‐1) is regulated in an allele‐specific manner
Authors: Zitnik G. D. , Martin G. M. 
Published: May 2005

AbstractThe murine “housekeeping” enzyme, cytosolic NADP‐isocitrate dehydrogenase (E.C. 1.1.1.42) (genetic locus:Idh‐1), exhibited a complex pattern of allele‐specific expression. Protein electrophoresis on cellulose‐acetate gels and determination of relative enzymatic activity by means of densitometry revealed that in heart tissue (but not liver tissue) of certain hybrid crosses the AA‐homodimer was underrepresented relative to total enzymatic activity, and the degree of underrepresentation changed during development. In mixtures of homozygous tissue extracts of heart tissue (but not liver tissue) the AA‐homodimer was underrepresented relative to the BB‐homodimer. Relative activity of allelic isozymes varied as a function of tissue (heart versus liver), age, and the parental source of the Idh‐1a allele, but did not vary as a function of sex.Allele‐specific expression was also exhibited in kidney tissue of the same animals. In adult male kidney tissue extracts from heterozygotes, the AA‐hornodimer was underrepresented relative to total enzymatic activity; in adult female kidney tissue extracts from heterozygotes, a more codominant phenotype was observed. Tissue extracts from immature hybrid animals exhibited a phenotype midway between the adult male and adult female phenotypes. Tissue extracts from castrated males exhibited a phenotype equivalent to that seen in females. Relative activity of allelic isozymes in kidney varied as a function of age and sex, but did not vary as a function of the parental source of the Idh‐1a allele.While cytosolic NADP‐IDH is a “housekeeping” enzyme, expressed in multiple tissues of the mouse, differences in the relative intensities of allelic isozyme bands provide evidence for tissue‐ and stage‐specific regulatory variation.
Action of the cubitus interruptus‐wallace mutant in Drosophila melanogaster: A study of leg morphology on mosaic and haplo‐4 flies
Authors: Benner D. B. 
Published: May 2005

AbstractThe fourth chromosome mutant cubitus interruptus‐Wallace(ciW) produces leg, wing, and body bristle aberrations. The effect on the wing is similar to that produced by cubitus interruptus‐dominant (ciD) which also has an influence on larval segmentation indicating that it has a regulatory function. Leg morphology of haplo‐4, ciW, and mosaic haplo‐4:diplo‐4, ci/ci+ flies was examined in an attempt to distinguish between a structural and a regulatory function by ciW. Aberrations recovered include failure of segment elongation, intersegmental gaps, duplication of bristles, and segments that are shorter than normal and of greater than normal diameter. Many of these effects are localized, suggesting that ciW may act to maintain cell positional reference. Increased local cell proliferation appears to be one manifestation of loss of the normal function.
Gene controlling a differentiation step in the quail melanocyte
Authors: Yamamoto Hiroaki , Ito Kazuo , Ishiguro Sei‐Ichi , Takeuchi Takuji 
Published: May 2005

AbstractAlbino mutation in animals blocks pigmentation owing to a deficiency in tyrosinase, although it does not affect the differentiation of colorless melanocytes from the neural crest. In the albino Japanese quail (al, sex‐linked), it was demonstrated that morphologically normal melanocytes differentiated from neural crest cells in culture and that these cells contained unmelanized melanosomes as expected for the mutant cells. The mutant melanocytes, however, were shown to exhibit tyrosinase activity in the Golgi‐endoplasmic reticulum‐lysosome region and in the Golgi vesicles. Our results seem to indicate that the mutation at the al locus affects the transport of tyrosinase from the Golgi area to melanosomes.
Influence of the major histocompatibility comp(MHC) on the response to and expression of H‐Y in rats
Authors: Desquenne‐Clark Lise , Chen Hong‐Duo , Silvers Willys K. 
Published: May 2005

AbstractThe influence of the major histocompatibility complex (MHC) on the survival of H‐Y‐incompatible skin grafts in rats has been determined by challenging normal and previously sensitized females of various isogenic and congenic strains with male trunk or ear skin isografts. The MHC's influence on the potency of H‐Y has also been evaluated by determining the survival of male parental strain ear skin grafts on sensitized (with F1 hybrid male cells) F1 hybrid females of two different MHC congenic strains. The results indicate that, as in mice, the MHC has a dual affect on H‐Y; it is involved in determining the ability of females to respond to the antigen as well as influencing its potency.
Tissue‐specific and developmental expression of human transthyretin gene in transgenic mice
Authors: Yamamura Ken‐Ichi , Wakasugi Shoji , Maeda Shuichiro , Inomoto Takeaki , Iwanaga Tomohisa , Uehira Masahiro , Araki Kimi , Miyazaki Jun‐Ichi , Shimada Kazunori 
Published: May 2005

AbstractTo analyze the regulation of transthyretin gene expression we have produced transgenic mice by microinjecting cloned human transthyretin genes into fertilized eggs of C57BL/6 mice. The 7.6‐kilobase (kb) human transthyretin gene containing about 500 base pairs (bp) in the upstream region was used for microinjection. Seven out of nine transgenic mice had detectable amounts of human transthyretin in serum when analyzed by enzyme‐linked immunosorbent assay.Transthyretin mRNA was detected in liver and yolk sac but not in other tissues including brain. The amount of mRNA was variable among transgenic mice and was about one‐tenth of mouse endogenous transthyretin mRNA. Human and mouse transthyretin mRNAs were detected in liver of fetus and yolk sac at 13 days of gestation and unlike yolk sac the level of mRNA in liver increased gradually during development and reached the maximum at around 17 days of gestation. Human transthyretin was associated with mouse transthyretin to form tetramers as judged from the dilution curve of enzyme‐linked immu‐nosorbent assay and the spur formation in Ouchterlony assay.
Testes of XX ↔ XY chimeric mice develop from fetal ovotestes
Authors: Bradbury Michael W. 
Published: May 2005

AbstractThe majority of XX ↔ XY chimeric mice develop into fertile males. The sexual differentiation of the gonads in these animals has been examined on days 12–14 postcoitum to determine if their development parallels that of normal testes. It was found that 50% of chimeric fetuses, the proportion predicted to be XX ↔ XY, had neither normal testes nor ovaries. Instead, ovotestes were present, with varying proportions of presumptive ovarian and testicular tissue. On day 12 the ovotestes were organized with testicular tissue in the central region and ovarian tissue at the craniad and/or caudad poles. In the more advanced fetuses there was evidence of regression of the ovarian portion, which would account for the testes found in adults. These results are discussed in light of current theories of sex determination and differentiation and what was previously known about gonads of sex mosaics.
Restriction enzyme evidence for Alu sequence‐mediated dispersion of microinjected genes in transgenic mice
Authors: Rubinstein Wendy S. , Gordon Jon W. 
Published: May 2005

AbstractA human bacteriophage clone containing adult β‐globin genes with four Alu sequences was microinjected to produce transgenic mice. Southern blot analysis on the spleen of a transgenic mouse revealed an unusual hybridization pattern that suggested extensive dispersion of human DNA throughout the mouse genome. This pattern was reproducible using several restriction enzymes, including a noncutting enzyme. The hybridization pattern was not observed in other tissues, and sequences were not detected in progeny using the bacteriophage probe. However, hybridization of spleen DNA of offspring against a human Alu probe revealed genetic transmission of human Alu sequences. The results suggest dispersion of microinjected Alu sequences throughout the genome.
Developmental consequences of autosomal aneuploidy in mammals
Authors: Gearhart John D. , Oster‐Granite Mary L. , Reeves Roger H. , Coyle Joseph T. 
Published: May 2005

AbstractAutosomal aneuploidy in mammals adversely affects developmental processes. In human beings, for example, trisomy 21 is the most frequent aneuploidy detected among newborns and the most common known genetic cause of mental retardation. In this review, several hypotheses are discussed that have been proposed to explain the mechanisms by which aneuploidy (especially trisomy) disrupts development. These mechanisms included specific gene dosage effects, generalized disruption of genetic homeostasis, and the influence of the parental origin of the duplicated chromosome. The availability of specific chromosomal rearrangements in mice, coupled with selective breeding schemes, permits generation of aneuploidy of specific chromosomes or chromosomal segments on controlled genetic backgrounds, thus enabling the systematic study of the causes and consequences of defined aneuploidy. Phenotypic characteristics associated with a number of specific aneuploidies in the mouse are discussed. Emphasis is placed on the effects of trisomy 16. Genetic homology between mouse chromosome 16 and human chromosome 21 has led investigators to suggest that analogous mechanisms will be responsible for the developmental abnormalities produced in these respective aneuploidies. Analysis of trisomy 16 mice from the organismal to the subcellular level has revealed a number of phenotypic characteristics (particularly neurobiologic ones) shared with human trisomy 21. The dosage effects of shared genes (or their products) may contribute to the development of these features.
Cloning and developmental regulation of α1 acid glycoprotein in swine
Authors: Stone R. T. , Maurer R. A. 
Published: May 2005

AbstractA cDNA clone of porcine alpha1 acid glycoprotein (α1AGP) has been isolated and sequenced. Sequence homologies between porcine, human, and rat indicate that porcine α1AGP is similar in structure to the rat and human proteins. RNA blots from days 40, 60, 80, and 110 fetal, newborn, and adult livers showed that α1AGP mRNA is relatively abundant throughout fetal development, particularly at the later stages and in the newborn; there is a rapid decline in abundance following birth. From birth to 3 days of age, there is a three‐ to four‐fold decline in abundance, and α1AGP mRNA is approximately 100 times less abundant in the adult liver than in that of perinatal pigs. Southern blots showed that α1AGP is probably a single‐copy gene. The isolation of a cloned cDNA for porcine α1AGP provides a tool to investigate the molecular mechanisms involved in the developmental regulation of the gene and to correlate changes in gene expression during development with fetal growth and well being.
Use of nuclear mutants in the analysis of chloroplast development
Authors: Taylor William C. , Barkan Alice , Martienssen Robert A. 
Published: May 2005

AbstractAlthough a wide range of mutations in the nuclear genome also affect chloroplast biogenesis, their pleiotropic nature often limits their use in studying nuclear genes that regulate or facilitate chloroplast development. However, many mutations that cause a high‐chlorophyll‐fluorescent (hcf) phenotype exhibit limited pleiotrophy, causing the loss of functionally related sets of chloroplast polypeptides. Several hcf mutations are described that result in the loss of one specific protein complex from the thylakoid membrane. Chlorplast and cytosolic mRNAs coding for component polypeptides of the missing complex are unaffected in the mutants, suggesting that each mutation disrupts some process in the synthesis and assembly of the missing complex. Another hcf mutation causes both the loss of three protein complexes and grossly abnormal thylakoid membrane structures. The primary effect of this mutation might be in the assembly of thylakoid membranes or in the stable accumulation of the three protein complexes. Two other hcf mutations are more pleiotropic. Hcf*−38 causes a quantitative reduction of many chloroplast proteins and a reduction of some chloroplast RNAs, including several splicing intermediates. Hcf*−7 causes a major reduction of all chloroplast‐encoded proteins examined. The range of pleiotropic effects of hcf mutations indicates that the mutations identify nuclear genes whose products are involved in a number of different steps in chloroplast devclopment. Because some of the mutations described have been generated by transposon insertions, they can be cloned using the transposon to identify the mutant allele.
Structure of the chloroplast psbA gene encoding the QB protein from Oryza sativa L.
Authors: Wu Nai‐Hu , Côté Jean‐Charles , Wu Ray 
Published: May 2005

AbstractThe light‐regulated chloroplast psbA gene encoding the QB protein has been cloned from rice (Oryza sativa L.), and the nucleotide sequence has been determined. Comparison of nucleotide sequences and derived amino acid sequences between species indicates a high degree of conservation of the primary structure. Comparison of promoter regions from the light‐inducible chloroplast psbA, rbcL, and psaA genes indicates conservation of the prokaryotic‐like promoter elements in all three genes and of a —21 box common only to psbA and rbcL promoter regions. No other putative regulatory signals were found based on nucleotide sequences.
Auxin (2,4‐dichlorophenoxyacetic acid) starvation and treatment with glucan elicitor isolated from Phytophthora megasperma induces similar responses in soybean‐cultured cell suspensions
Authors: Leguay J. J. , Jouanneau J. P. 
Published: May 2005

AbstractAuxin (2,4‐dichlorophenoxyacetic acid) starvation of soybean cell suspension leads to the arrest of cell division after about 4 days. Readdition of 4 μM of auxin enables cells to divide again after a lag phase of 1 day. Accumulation of a well‐known isoflavonoid‐derived phytoalexin (glyceollin) and a highly elevated catalytic activity of two of the enzymes associated with glyceollin biosynthesis, phenylalanine ammonia‐lyase and chalcone isomerase, is described. Moreover, stimulation of catalytic activity of the enzymes chitinase and β 1,3‐glucanase, which are involved in plant defense against pathogens, is observed at the same time. By comparing the patterns of in vitro protein synthesis, we have identified groups of polypeptides whose synthesis is either positively or negatively regulated by auxin. Some of these polypeptides are also induced by fungal elicitor treatment. Our results provide evidence of a dual control by auxin and fungal elicitor working in an opposite manner on the inducibility of enzymes and proteins that play a role in the induced defense response of soybean.
Developmental genetics of the soybean urease isozymes
Authors: Holland Mark A. , Griffin Jeffrey D. , Elise Meyer‐Bothling L. , Polacco Joseph C. 
Published: May 2005

AbstractThe soybean (Glycine max [L.] Merr.) contains two urease isozymes whose expression is regulated in a tissue‐specific and temporal manner. The ubiquitous urease is expressed in all tissues examined (leaf, embryo, seed coat, cell culture); the embryo‐specific urease is synthesized exclusively in the developing embryo. The embryo‐specific urease accumulates during seed development while the ubiquitous urease is found in highest levels during early development of both leaves and seeds. We have isolated mutants which fall in three phenotypic classes lacking one or both urease isozyme activities. Genetic analysis has thus far identified three unlinked loci which control the expression of urease(s). Genomic and cDNA clones of urease structural genes have also been recovered and we are working to assign these to genetic loci by sequence and RFLP analyses. That the ubiquitous urease isozyme is expressed in cell culture makes it possible to include cell culture in physiological and developmental studies. Additionally, we have developed direct selections for urease‐negative mutants, and their revertants, in cell culture. These selections will facilitate the study of the expression of cloned urease genes in genetically transformed tissue.
Nuclear genes that alter assembly of the chlorophyll a/b light‐harvesting complex in Zea mays
Authors: Polacco Mary , Vann Carolyn , Rosenkrans Leonard , Harding Scott 
Published: May 2005

AbstractThe major chlorophyll a/b light harvesting complex (LHCII) of mesophyll chloroplasts is normally assembled late during chloroplast morphogenesis. LHCII occurs at greatly reduced levels in bundle sheath chloroplasts of maize. In order to understand the normal regulatory mechanisms we are examining nuclear maize mutants that alter either (1) the assembly timing or (2) the steady state level of LHCII in mature mesophyll thylakoids. We have found a delayed greening mutant, v24 (on chromosome arm 2L), that unmasks a second unlinked locus, Mof*, that can mediate LHCII assembly timing. The polypeptides of LHCII are encoded by the nuclear multigene cab family. We find that two alleles at Mof* regulate the steady state level of cab mRNA in parallel to their effect on LHCII assembly timing: The genotype Mof*‐1 Mof*‐1 v24 v24 corresponds to reduced cab mRNA and late LHCII assembly timing, while Mof*‐2 Mof*‐2 v24 v24 corresponds to reduced cab mRNA and late LHCII assembly timing. A second group of mutations (Oy‐700, pg11 and pg12 reduces LHCII levels in mesophyll thylakoids. This is the first report that pg11 and pg12) reduce the LHCII of mesophyll thylakoids. The basis of pg11 and pg12 is unknown. Mutations at the Oy locus block the chlorophyll biosynthetic enzyme, protopor‐phyrin IX Mg‐chelatase. Heterozygotes of the codominant mutation Oy‐700 with the normal allele (Oy) have reduced LHCII. We have defined genetic backgrounds that suppress and those that do not suppress the Oy‐700 Oy phenotype under certain conditions: (1) reduced light intensities (200 μE cm−2 sec−1) and/or (2) plant maturity.
Histone genes in higher plants: Organization and expression
Authors: Chaubet Nicole , Chaboute Marie‐Edith , Philipps Gabriel , Gigot Claude 
Published: May 2005

AbstractThe general structure of the plant histone genes has been deduced from the comparison of the nucleotide sequences of ten H3 and H4 genes of maize (3 H3 and 3 H4) and Arabidopsis thaliana (2 H3 and 2 H4). The five H3 and five H4 genes encode the same proteins, respectively. The 5′‐flanking regions contain the classical histone gene‐specific consensus sequences. In addition, a conserved octanucleotide CGCGGATC was found in all plant histone genes at 200–250 nucleotides before the initiation codon.All six maize H3 and H4 genes are transcribed during early germination as shown by nuclease S1 mapping and reverse transcriptase primer extension experiments. The mRNA 5′‐ends are located within the consensus sequence CCAA/CT/C. The 3′‐ends lack the classical T‐hyphenated dGC‐rich palindromic structure and possess long nontranslated sequences.In both plants the multiple copies of the H3 and H4 genes are organized into multigenic families. The genes of each family show a similar proximal environment, suggesting that they originate from the duplication of a common ancestor.
Expression of selected nuclear genes during leaf development in barley
Authors: Barkardottir R. B. , Jensen B. F. , Kreiberg J. D. , Nielsen P. S. , Gausing K. 
Published: May 2005

AbstractGroups of cDNA clones encoding abundant leaf proteins or derived from genes (gene families) with other features of interest have been selected from a barley leaf cDNA library. The characteriaztion of nine of the groups is summarized and includes information on the tissue specificity and light dependence of expression of their corresponding genes. Different types of control of gene expression are represented in the collection: leaf‐specific expression, both stimulated and inhibited by light, constitutive expression, and expression that is maximal in one case in coleoptiles and in two cases in meristematic tissue. For the light‐stimulated genes (gene families) encoding chloroplast proteins (Cab, RbcS, and plastocyanin), relative and absolute levels of messengers were determined as a function of cell age in sections of 7‐day‐old barley leaves grown under diurnal conditions. Key parameters of cell growth (protein, RNA, and DNA accumulation) were determined in the same leaf sections. The main conclusions of the expression studies are as follows: (1) Light is in no case a requirement for gene expression although it has significant stimulatory effect on some genes; (2) weak expression of some genes coding for chloroplast proteins was detected in the leaf‐like, white coleoptiles, whereas expression in roots could not be detected; (3) The cab, rbcS, and plastocyanin genes are expressed very early during leaf cell differentiation, when the plastids morphologically are still in their amyloplast‐amoeboid stages; (4) The expression of the cab, rbcS, and plastocyanin genes is not coordinated during leaf cell development.
Age‐dependent variation for inducibility of metallothionein genes in mouse liver by cadmium
Authors: Thomas David J. , Morris Sheldon , Huang P. C. 
Published: May 2005

AbstractCadmium is a toxic metal that induces the expression of metallothionein genes in many tissues and that binds avidly to metallothionein, a soluble transition metal binding protein. The present study examined the temporal pattern and magnitude of accumulation of metallothionein mRNA in liver of C57BL/6J mice of various ages treated with cadmium. In adult female mice, accumulation was dependent on the dosage level of cadmium and related to the concentration of this metal in liver. The accumulation of metallothionein mRNA in liver depended on age at exposure to cadmium. Intraperitoneal administration of 2 mg of cadmium per kg provoked small increases (two‐ to threefold) in levels of metallothionein mRNA in livers of 7‐ and 14‐day‐old mice. In contrast, cadmium treatment of 28‐ and 56‐day‐old mice resulted in 12‐ to 19‐fold increases in levels of metallothionein mRNA in liver with maximum increases occurring 3 to 4 hr after treatment. Because similar patterns for the accumulation of cadmium of liver were found in 7‐, 28‐, and 56‐day‐old mice, observed age‐dependent differences in induction of metallothionein mRNA in liver were probably not due to differences in the accumulation of cadmium in this organ. Taken together, these data suggest that tissue‐specific factors controlling the expression of metallothionein genes may account for developmental variation in the inducibility of these genes by cadmium. Ontogenic variation in accumulation of metallothionein mRNA after cadmium treatment may be a factor in developmental variation in the acute lethality of cadmium in C57BL/6J mice.
Drosophila genes encoding maternal‐specific and maternal‐differential RNAs
Authors: Underwood Eileen M. , Lengyel Judith A. 
Published: May 2005

AbstractThe unique cellular and genetic events which occur during the first few hours of Drosophila embryogenesis suggest that there are genes whose function is entirely or largely limited to this stage; this is supported by both genetic and molecular evidence. To identify some of these genes and characterize the relative contribution of specifically maternal and specifically zygotic transcription to early embryogenesis, we used competition and differential screening of a Drosophila genomic DNA library to obtain blastoderm‐ and maternal‐differential sequences [Roark et al.: Dev Biol 109:476–488, 1985]. We describe here the Eco RI restriction fragments, chromosomal location, and size and developmental pattern of expression of the RNAs transcribed from 19 maternal‐differential sequences. Five sequences encode maternal‐specific transcripts (50‐150‐fold more abundant in maternal RNA than at any other stage). The maternal‐specific and maternal‐differential sequences are located at single sites on all major chromosome arms. Comparison of these sites with the sites of presently mapped maternal‐effect genes shows several possible correlations, including one region containing three maternal‐effect lethal mutations and two maternalspecific sequences.