Showing papers by "University of Oregon published in 1992"
TL;DR: In this article, the logs of the age-specific death rates are modeled as a linear function of an unobserved period-specific intensity index, with parameters depending on age, and the model is fit to the matrix of U.S. death rates using the singular value decomposition (SVD) method.
Abstract: Time series methods are used to make long-run forecasts, with confidence intervals, of age-specific mortality in the United States from 1990 to 2065. First, the logs of the age-specific death rates are modeled as a linear function of an unobserved period-specific intensity index, with parameters depending on age. This model is fit to the matrix of U.S. death rates, 1933 to 1987, using the singular value decomposition (SVD) method; it accounts for almost all the variance over time in age-specific death rates as a group. Whereas e 0 has risen at a decreasing rate over the century and has decreasing variability, k(t) declines at a roughly constant rate and has roughly constant variability, facilitating forecasting. k(t), which indexes the intensity of mortality, is next modeled as a time series (specifically, a random walk with drift) and forecast. The method performs very well on within-sample forecasts, and the forecasts are insensitive to reductions in the length of the base period from 90 to 30 ...
1,930 citations
TL;DR: Deviations from the force curves predicted by the freely jointed chain model suggest that DNA has significant local curvature in solution, and the effect of bend-inducing cis-diamminedichloroplatinum (II) was large and supports the hypothesis of natural curvatures in DNA.
Abstract: Single DNA molecules were chemically attached by one end to a glass surface and by their other end to a magnetic bead. Equilibrium positions of the beads were observed in an optical microscope while the beads were acted on by known magnetic and hydrodynamic forces. Extension versus force curves were obtained for individual DNA molecules at three different salt concentrations with forces between 10(-14) and 10(-11) newtons. Deviations from the force curves predicted by the freely jointed chain model suggest that DNA has significant local curvature in solution. Ethidium bromide and 4',6-diamidino-2-phenylindole had little effect on the elastic response of the molecules, but their extent of intercalation was directly measured. Conversely, the effect of bend-inducing cis-diamminedichloroplatinum (II) was large and supports the hypothesis of natural curvature in DNA.
1,826 citations
Posted Content•
TL;DR: Knowledge intensive firms (KIFs) specialize in expertise, especially esoteric knowledge that few other firms possess as mentioned in this paper, and their ability to satisfy clients depends on the close relations that some of KIFs' personnel develop with specific clients.
Abstract: Knowledge-intensive firms (KIFs) specialize in expertise, especially esoteric knowledge that few other firms possess. KIFs must keep their knowledge up-to-date, so they need to learn continually. However, their ability to satisfy clients depends on the close relations that some of KIFs' personnel develop with specific clients.
1,406 citations
TL;DR: The collection of vacuolar protein sorting mutants (vps mutants) in Saccharomyces cerevisiae comprises of 41 complementation groups and it is suggested that this organelle may represent an exaggerated endosome-like compartment.
Abstract: The collection of vacuolar protein sorting mutants (vps mutants) in Saccharomyces cerevisiae comprises of 41 complementation groups. The vacuoles in these mutant strains were examined using immunof...
846 citations
01 Jan 1992
556 citations
TL;DR: Reproducible images of uncoated DNA in the atomic force microscope (AFM) have been obtained by imaging plasmid DNA on mica in n-propanol by increasing the force applied by the AFM tip at selected locations.
Abstract: Reproducible images of uncoated DNA in the atomic force microscope (AFM) have been obtained by imaging plasmid DNA on mica in n-propanol. Specially sharpened AFM tips give images with reproducible features several nanometers in size along the DNA. Plasmids can be dissected in propanol by increasing the force applied by the AFM tip at selected locations.
493 citations
TL;DR: In this paper, the authors present a framework of social amplification of risk which integrates the technical assessment and the social experience of risk, and propose that the social and economic impacts of an adverse event are determined not only by the direct physical consequences of the event, but by the interaction of psychological, cultural, social, and institutional processes that amplify or attenuate public experiences of risk and result in secondary impacts.
Abstract: The article presents the framework of social amplification of risk which integrates the technical assessment and the social experience of risk. Risk perception research has revealed that contextual factors shape individual risk estimations and evaluations. Identification of these factors, such as voluntariness, personal ability to influence risks, familiarity with the hazard, and catastrophic potential, provides useful information about the elements that individuals consider in constructing their interpretation of risks. In addition, analyses of people's heuristics in making inferences have shed some light on how risk information is generalized and evaluated intuitively. These psychological studies fail to explain, however, why individuals attend to certain characteristics of risks and ignore others. Furthermore, in focusing only on the individual as an information processor, these studies exclude from the analysis the social and cultural variance of risk interpretations. The social amplification framework postulates that the social and economic impacts of an adverse event are determined not only by the direct physical consequences of the event, but by the interaction of psychological, cultural, social, and institutional processes that amplify or attenuate public experience of risk and result in secondary impacts.
485 citations
TL;DR: In this article, two studies were employed to develop a self-report temperament measure for the early adolescent period based on the work of Rothbart and colleagues with adults and focused on emoti...
Abstract: Two studies were employed to develop a self-report temperament measure for the early adolescent period. The measure was based on the work of Rothbart and colleagues with adults and focused on emoti...
461 citations
TL;DR: Routine and reproducible imaging of DNA molecules in air with the scanning force microscope (SFM) has been accomplished and the first images of the Escherichia coli RNA polymerase-DNA complex have also been obtained.
Abstract: Routine and reproducible imaging of DNA molecules in air with the scanning force microscope (SFM) has been accomplished. Circular molecules of plasmid DNA were deposited onto red mica and imaged under various relative humidities. In related experiments, the first images of the Escherichia coli RNA polymerase-DNA complex have also been obtained. This has been possible by (1) the use of specially modified SFM tips with a consistent radius of curvature of 10 nm or less, to minimize the amount of image distortion introduced by the finite dimensions of commercially available tips, (2) the optimization of a method to deposit and bind DNA molecules to the mica surface in a stable fashion, and (3) careful control of the sample humidity, to prevent solvation of the molecules and detachment from the surface by the scanning tip or stylus. Contact forces in the range of a few nanonewtons are routinely possible in air and in the presence of residual humidity. The spatial resolution of the images appears determined by the radius of curvature of the modified styli, which can be estimated directly from the apparent widths of the DNA molecules in the images.
432 citations
TL;DR: The results of these studies demonstrate that the b-HLH domain of B and most of its carboxyl terminus can be deleted with only a partial loss of B-protein function, and suggest that the regulation of the maize anthocyanin pigmentation pathway involves a direct interaction between members of two distinct classes of transcriptional activators.
Abstract: The B, R, C1, and Pl genes regulating the maize anthocyanin pigment biosynthetic pathway encode tissue-specific transcriptional activators. B and R are functionally duplicate genes that encode proteins with the basic-helix-loop-helix (b-HLH) motif found in Myc proteins. C1 and Pl encode functionally duplicate proteins with homology to the DNA-binding domain of Myb proteins. A member of the b-HLH family (B or R) and a member of the myb family (C1 or Pl) are both required for anthocyanin pigmentation. Transient assays in maize and yeast were used to analyze the functional domains of the B protein and its interaction with C1. The results of these studies demonstrate that the b-HLH domain of B and most of its carboxyl terminus can be deleted with only a partial loss of B-protein function. In contrast, relatively small deletions within the B amino-terminal-coding sequence resulted in no trans-activation. Analysis of fusion constructs encoding the DNA-binding domain of yeast GAL4 and portions of B failed to reveal a transcriptional activation domain in the B protein. However, an amino-terminal domain of B was found to recruit a transcriptional activation domain by an interaction with C1. Formation of this complex resulted in the activation of a synthetic promoter containing GAL4 recognition sites, demonstrating that this interaction does not require the normal target promoters for B and C1. B and C1 fusions with yeast GAL4 DNA-binding and transcriptional activation domains were also found to interact when synthesized and assayed in yeast. The domains responsible for this interaction map to a region that contains the Myb homologous repeats of the C1 protein and to the amino terminus of the B protein, which does not contain the b-HLH motif. These studies suggest that the regulation of the maize anthocyanin pigmentation pathway involves a direct interaction between members of two distinct classes of transcriptional activators.
420 citations
TL;DR: Current concepts, controversies, and management of cutaneous squamous cell carcinoma (excluding the lip and oral mucosa) are addressed.
Abstract: The striking impression obtained from reviewing the cancer literature is how difficult it is to analyze the data for answers to many important biologic, behavioral, prognostic, and therapeutic questions about squamous cell carcinoma of the skin. This article addresses current concepts, controversies, and management of cutaneous squamous cell carcinoma (excluding the lip and oral mucosa).
TL;DR: The reading fluency, a combination of decoding and comprehension, is defined by as mentioned in this paper as "reading fluency" which is defined as "a combination of decoder and comprehension".
Abstract: Reading traditionally is characterized as having two major components, decoding and comprehension. Published reading tests are created using these two components. Reading fluency, a combination of ...
TL;DR: Infants' sensitivity to acoustic correlates of phrasal units in English is examined to suggest that pitch changes and in some cases durational changes are potential cues that infants might be using to make their discriminations.
TL;DR: Infants' orienting of attention undergoes marked development in the first six months of life, and changes in attentional control appear to be related to infants' susceptibility to distress.
Abstract: Infants' orienting of attention undergoes marked development in the first six months of life, and changes in attentional control appear to be related to infants' susceptibility to distress.
TL;DR: The results demonstrate that modulation of the kinase activity does not require association-dissociation of the ternary complex, which suggests that the receptor signal is transduced through conformational changes in the teranary complex rather than through changes of the association of the Kinase CheA with receptor and/or CheW.
TL;DR: Observations provide strong evidence for the proposed protective role of scytonemin, as a passive UV‐A sunscreen, in cyanobacteria.
Abstract: The proposed photoprotective role of the UV-A absorbing, extracellular pigment scytonemin was studied in the terrestrial cyanobacterium Chlorogloeopsis sp. strain O-89-Cgs(1). UV-A (315-400 nm) caused growth delay, cell growth restarting only when scytonemin had accumulated in the extracellular envelopes. Cultures with scytonemin were more resistant to photoinhibition of photosynthesis than cultures without scytonemin, the differential resistance being much greater to UV-A-caused photoinhibition than to photoinhibition caused by visible light. The presence of scytonemin in the extracellular envelopes was correlated with the inability of UV-A radiation to induce strong photopigment fluorescence (685 nm emission), regardless of the specific content os photosynthetic pigments. The physical removal of the scytonemin containing extracellular envelopes brought about the loss of UV-A resistance as measured by photobleaching rates of chlorophyll a under conditions of physiological inactivity (desiccation). These observations provide strong evidence for the proposed protective role of scytonemin, as a passive UV-A sunscreen, in cyanobacteria.
01 Jan 1992
TL;DR: The chapter presents a hypothesis that states that the brain's attention system produces the contents of awareness in the same way as its visual system organizes the way the visual world is perceived.
Abstract: Publisher Summary This chapter describes three networks involved in selective attention: (1) the posterior attention system, (2) the anterior attention system, and (3) the vigilance system. The combination of the functions of these three networks produces a subjective state of readiness, referred to as the clearing of consciousness, which is both alert and free of conscious content. The chapter presents a hypothesis that states that the brain's attention system produces the contents of awareness in the same way as its visual system organizes the way the visual world is perceived. The posterior attention network is involved in orienting to sensory stimuli. When one attends to a location in visual space, not only is information at that location increased in processing efficiency but information observed at other locations is also captured with lesser efficiency than what it would be if attention had not been paid to the selected location. In humans, the detection of events is often signaled by a verbal response. The anterior attention system is presupposed to be the main aspect involved in detection tasks and depends on the number of targets presented. Another close connection between awareness, control, and the anterior cingulate arises from the vigilance network. This system involves locus coeruleus norepinephrine input to the cortex. When subjects are required to maintain the alert state in the foreperiod of a reaction time task or when they have to attend to a source of signals while waiting for an infrequent target to occur, there is a strong activity in this system.
TL;DR: The grammar of topic marking as discussed by the authors is a set of processing instructions that cue two major cognitive systems: attention and episodic memory, and it has been shown that the grammar does not directly interact with the text, but rather interacts with the mind that produces or interprets the text.
Abstract: Referents (\"topics\") serve as file labels in the episodic memory for stored text. The grammar of topic marking is a set of processing instructions that cue two major cognitive systems: attention and episodic memory. The cataphoric elements in the grammar tell the hearer/reader whether the referent is important and thus needs to be activated and then used as file label for a newly opened storage file in the episodic memory. Unimportant referents are not activated but rather are filed as new information in the currently active memory file. The anaphoric elements in the grammar tell the hearer/reader where to search for the topic in the existing storage structure of episodic memory. Coding a referent by zero or unstressed pronoun signals that it is the currently active topic, that it should retain its activation, and that incoming information should continue to be filed under its label. When a currently inactive referent is coded as definite and important, various grammatical devices tell the hear er j reader where to search for it in episodic memory. Following search and retrieval, the referent is then activated, and new incoming information is filed under its label. 1. Grammar, text, and mind In attempting to understand the phenomenon of topicality, linguists have relied heavily on studying the correlations between grammar and communicative context, most typically on the distribution of grammar in text. This grammar-in-text methodology has been indispensable in helping us understand the discourse-functional correlates of grammar. However valuable as a heuristic, this method has inherent drawbacks. Chief among those is the fact that in actual communicative behavior, the grammar does not directly interact with the TEXT. Rather, the grammar interacts with the MIND that produces or interprets the text. What I propose to do Linguistics 30 (1992), 5-55 0024-3949/92/0030-0005 $2.00 © Walter de Gruyter
TL;DR: This paper showed that amphibole breaks down from 900 to 950 °C, producing garnet, orthopyroxene, magnetite, titanomagnetite, and granitic melt.
Abstract: Vapor-absent melting experiments on a biotite- and amphibole-bearing, Archean tonalitic gneiss (AGC150) at 10 kbar and 875 to 1050 °C show that amphibole breaks down from 900 to 950 °C, producing garnet, orthopyroxene, and granitic melt. Biotite-dehydration melting produces <10 wt% melt up to 950 °C via incongruent melting reactions that produce garnet, orthopyroxene, and titanomagnetite. Widespread biotite-dehydration melting occurs between 950 and 975 °C and produces orthopyroxene, magnetite, titanomagnetite, and ∼20 wt% fluorine-rich melt (up to 0.31 wt% F). Minor F-rich (2.7 wt%) biotite is present even at 1000 °C. Our experiments show that, under vapor-absent conditions, intrusion of hot, mantle-derived magmas into the lower crust is necessary to initiate widespread biotite-dehydration melting in rocks with compositions like AGC150. We propose that the high thermal stability of biotite in AGC150 suggests that this rock is residual after a previous episode of partial dehydroxylation that left behind somewhat F-enriched biotite. We show that dehydration melting of such F-enriched biotite produces F-rich granitic liquids, with compositions within the range of A-type granite, and leaves behind a granulitic residue consisting of orthopyroxene, plagioclase, quartz, titanomagnetite, and magnetite.
TL;DR: In this paper, the use of two categories of estimators for probit models with spatial autocorrelation is discussed. And the EM algorithm is applied to models derived using the spatial expansion method, which only requires weighted least squares.
Abstract: . Commonly-employed spatial autocorrelation models imply heteroskedastic errors, but heteroskedasticity causes probit to be inconsistent. This paper proposes and illustrates the use of two categories of estimators for probit models with spatial autocorrelation. One category is based on the EM algorithm, and requires repeated application of a maximum-likelihood estimator. The other category, which can be applied to models derived using the spatial expansion method, only requires weighted least squares.
TL;DR: From a ste4 deletion strain, both dominant and recessive suppressors that show increased transcription of pheromone responsive genes and have regained the ability to mate, albeit at a low level are isolated.
Abstract: STE4 encodes the beta-subunit of a heterotrimeric guanine nucleotide-binding protein (G protein) that is an early and essential component of the pheromone signal transduction pathway. From a ste4 deletion strain we have isolated both dominant and recessive suppressors that show increased transcription of pheromone responsive genes and have regained the ability to mate, albeit at a low level. Each of these suppressor mutations suppresses ste4 and ste5 deletions but not deletions in STE7, STE11, or STE12. Among the dominant mutations, we have identified two alleles of STE11, a gene that encodes a protein kinase activity essential for mating. One allele contains an alteration in the putative regulatory domain of the protein kinase; the second allele has an alteration in the catalytic site. In strains carrying these mutations, a second protein kinase required for mating, STE7, becomes hyperphosphorylated, just as it does in wild-type cells treated with pheromone. Thus, a protein kinase cascade appears to be an essential feature of the response pathway and probably connects the receptor/G protein to an identified transcription factor, STE12.
TL;DR: These experiments suggest that readers form explicit, lifelike, mental representations of fictional characters' emotional states, and readers form these representations as a normal part of reading comprehension.
Abstract: Subjects read stories that described concrete actions, such as a main character stealing money from a store where his best friend worked and later learning that his friend had been fired. Following each story, subjects read a target sentence that contained an emotion word that either matched the emotional state implied by the story (e.g. guilt) or mismatched that emotional state. In Experiment 1, target sentences were read more slowly when the mismatched emotion words were the perceived opposites of the emotional states implied by the stories (e.g. pride). In Experiment 2, target sentences were read more slowly when the mismatched emotion words shared the affective valence of the implied emotional state; therefore, readers must represent more than simply the affective valence of the emotional states. Instead of reading target sentences that contained matching versus mismatching emotion words, subjects in Experiment 3 simply pronounced matching versus mismatching emotion words. Mismatching emotion...
Journal Article•
TL;DR: Pax-6 expression appears during processes when cell-to-cell signalling is thought to be important, for example during induction of the eye and regionalization of the spinal cord and brain, suggesting that it may be one component mediating the response to inductive interactions.
Abstract: Despite obvious differences in the patterns of early embryonic development, vertebrates share a number of developmental mechanisms and control genes, suggesting that they use similar genetic programs at some stages of development. To examine this idea, we isolated and characterized one such gene, pax-6, a member of the pax gene family, from the zebrafish Brachydanio rerio and determined the evolutionary conservation in the structure and expression of this gene by comparison to its homolog in mice. We found two alternatively spliced forms of the zebrafish pax-6 message. Sequence and expression pattern of the zebrafish pax-6 gene are remarkably similar to its murine homolog. pax-6 expression begins during early neurulation. A stripe of cells in the neuroectoderm, including the prospective diencephalon and a part of the telencephalon, expresses pax-6 as well as the hindbrain and the ventral spinal cord extending from the level of the first rhombomere to the posterior end of the CNS. During later development more limited regions of the brain including the eye, the olfactory bulb and the pituitary gland express pax-6. Cells at the midbrain-hindbrain junction express eng genes and are separated from the neighboring pax-6 regions by several cells that express neither gene, indicating a complex subdivision of this region. pax-6 expression appears during processes when cell-to-cell signalling is thought to be important, for example during induction of the eye and regionalization of the spinal cord and brain, suggesting that it may be one component mediating the response to inductive interactions.
TL;DR: Observations suggest that functional PDGFR alpha can affect crest development both directly, by acting as a cell growth and/or survival stimulus for populations of non-neurogenic crest cells, and indirectly, by affecting the structure of the matrix environment through which such cells move.
Abstract: The Patch (Ph) mutation in mice is a deletion of the gene encoding the platelet-derived growth factor receptor alpha subunit (PDGFR alpha). Patch is a recessive lethal recognized in heterozygotes by its effect on the pattern of neural crest-derived pigment cells, and in homozygous mutant embryos by visible defects in craniofacial structures. Since both pigment cells and craniofacial structures are derived from the neural crest, we have examined the differentiation of other crest cell-derived structures in Ph/Ph mutants to assess which crest cell populations are adversely affected by this mutation. Defects were found in many structures populated by non-neuronal derivatives of cranial crest cells including the thymus, the outflow tract of the heart, cornea, and teeth. In contrast, crest-derived neurons in both the head and trunk appeared normal. The expression pattern of PDGFR alpha mRNA was determined in normal embryos and was compared with the defects present in Ph/Ph embryos. PDGFR alpha mRNA was expressed at high levels in the non-neuronal derivatives of the cranial neural crest but was not detected in the crest cell neuronal derivatives. These results suggest that functional PDGF alpha is required for the normal development of many non-neuronal crest-derived structures but not for the development of crest-derived neuronal structures. Abnormal development of the non-neuronal crest cells in Ph/Ph embryos was also correlated with an increase in the diameter of the proteoglycan-containing granules within the crest cell migratory spaces. This change in matrix structure was observed both before and after crest cells had entered these spaces. Taken together, these observations suggest that functional PDGFR alpha can affect crest development both directly, by acting as a cell growth and/or survival stimulus for populations of non-neurogenic crest cells, and indirectly, by affecting the structure of the matrix environment through which such cells move.
TL;DR: The results indicate the importance of mutation and migration in maintaining quantitative genetic variance within small local populations, and contrast with Wright's classical conclusion that at least one immigrant per island every other generation is necessary.
Abstract: Additive genetic variance maintained by mutation in a selectively neutral quantitative character is analyzed for an ideal population distributed on n islands, each with local effective size N, that exchange migrants at a small rate, m. In a stable population structure, the expected genetic variance maintained within islands is identical to that in a panmictic population of the same total size, regardless of the migration rate (m > 0). This result contrasts with Wright's classical conclusion, based on inbreeding coefficients, that at least one immigrant per island every other generation (Nm > ½) is necessary for the genetic variance within local populations to approach that under panmixia. The expected genetic variance maintained among islands is inversely proportional to m and increases with the number of islands, but is independent of N. Local extinction and colonization diminish the genetic variance maintained within islands by reducing the effective size of island populations through the founder effect, although the expected genetic variance within islands is nearly as large as that in a panmictic population of the same total effective size. If the founders of new colonies originate from more than one island, rates of local extinction and colonization larger than about twice the migration rate will substantially reduce the genetic variance maintained among islands. These results indicate the importance of mutation and migration in maintaining quantitative genetic variance within small local populations.
TL;DR: Octreotide effectively decreased GH and IGF-1 concentrations in 53% and 68% of patients, respectively, and the higher dose resulted in increased frequency of tumor shrinkage but added no biochemical or clinical benefit.
Abstract: OBJECTIVE To determine the effects of the somatostatin analog, octreotide acetate, in patients with acromegaly. DESIGN Double-blind, randomized trial. SETTING Fourteen university-affiliated medical centers. PATIENTS One hundred fifteen acromegalic patients, 70% of whom had persistent disease after pituitary surgery or radiotherapy. INTERVENTION Subcutaneous octreotide, 100 micrograms, or placebo every 8 hours for 4 weeks. Four weeks after the end of treatment, patients were randomized to receive 100 or 250 micrograms octreotide subcutaneously every 8 hours for 6 months. RESULTS After 2 weeks of treatment, a single 100-micrograms injection reduced mean serum growth hormone (GH) to 30% of the pretreatment concentration within 2 hours. The integrated mean GH level was reduced over 8 hours from 39 +/- 11 micrograms/L to 9 +/- 2 micrograms/L (P less than 0.001). Mean plasma insulin-like growth factor-1 (IGF-1) was reduced from 5100 +/- 400 U/L to 2400 +/- 400 U/L (P less than 0.001). After 6 months, the mean GH was reduced from 39 +/- 13 to 15 +/- 4 micrograms/L by 300 micrograms of octreotide and from 29 +/- 5 micrograms/L to 9 +/- 2 micrograms/L by 750 micrograms of octreotide daily. The mean IGF-1 concentration was suppressed to 2100 +/- 300 and 2500 +/- 400 U/L after 300 and 750 micrograms octreotide, respectively. Integrated mean GH levels were reduced to < 5 micrograms/L in 53% (95% CI, 39% to 67%) and 49% (CI, 35% to 63%), and IGF-1 levels were normal in 68% (CI, 54% to 82%) and 55% (CI, 40% to 70%) of patients receiving low- and high-dose octreotide, respectively. A substantial decrease in headache, amount of perspiration, joint pain, and finger circumference occurred in two thirds of the patients. The pituitary size was reduced in 19% (CI, 5% to 33%) and 37% (CI, 22% to 52%) of patients receiving 6 months of low- and high-dose octreotide, respectively. Ten percent and 13% of patients in each treatment group developed transient diarrhea; 10% and 14%, biliary sludge; and 6% and 18%, cholelithiasis, respectively. CONCLUSION Octreotide effectively decreased GH and IGF-1 concentrations in 53% and 68% of patients, respectively. The higher dose resulted in increased frequency of tumor shrinkage but added no biochemical or clinical benefit.
TL;DR: In this paper, a new algorithm for quantifying jet production in e+e− annihilation was proposed, based on clustering according to relative transverse momentum, which is expected to exhibit similar theoretical properties of exponentiation at small jet resolution.
TL;DR: A simple method of substrate preparation for imaging circular DNA molecules with the scanning force microscope (SFM) on mica that has been soaked in magnesium acetate, sonicated and glow-discharged is presented.
TL;DR: It is proposed that the fates and patterning of cells in zebrafish embryos may be regulated by the coordinate expression of particular combinations of these closely related homeoproteins.
Abstract: We have identified three genes, expressed in zebrafish embryos, that are members of the engrailed gene family. On the basis of sequence comparisons and analyses of their expression patterns, we suggest that two of these genes, eng2 and eng3, are closely related to the En-2 gene of other vertebrates. The third gene, eng1, is probably the zebrafish homolog of En-1. Subsets of cells at the developing junction between the midbrain and hindbrain express three different combinations of these genes, revealing a previously unknown complexity of this region of the CNS. Other cells, for example, jaw and myotomal muscle precursors, express two of the three genes in combinations which, in the myotomal muscles, change during development. Cells in the developing hindbrain and fins express only a single engrailed gene. We propose that the fates and patterning of these cells may be regulated by the coordinate expression of particular combinations of these closely related homeoproteins.