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A Dill

Publications and source records attributed to A Dill.

11 recordsLinked to original sources
PubMed2001

The DELLA motif is essential for gibberellin-induced degradation of RGA.

RGA and GAI are homologous genes that encode putative transcriptional regulators that repress gibberellin (GA) signaling in Arabidopsis. Previously we showed that the green fluorescent protein (GFP)-RGA fusion protein is localized to the nucleus in transgenic Arabidopsis, and expression of this fusion protein rescues the rga null mutation. The GA signal seems to derepress the GA response pathway by degrading the repressor protein RGA. The GA-insensitive, semidominant, semidwarf gai-1 mutant encodes a mutant protein with a 17-amino acid deletion within the DELLA domain of GAI. It was hypothesized that this mutation turns the gai protein into a constitutive repressor of GA signaling. Because the sequences missing in gai-1 are identical between GAI and RGA, we tested whether an identical mutation (rga-Delta 17) in the RGA gene would confer a phenotype similar to gai-1. We demonstrated that expression of rga-Delta 17 or GFP-(rga-Delta 17) under the control of the RGA promoter caused a GA-unresponsive severe dwarf phenotype in transgenic Arabidopsis. Analysis of the mRNA levels of a GA biosynthetic gene, GA4, showed that the feedback control of GA biosynthesis in these transgenic plants was less responsive to GA than that in wild type. Immunoblot and confocal microscopy analyses indicated that rga-Delta17 and GFP-(rga-Delta 17) proteins were resistant to degradation after GA application. Our results illustrate that the DELLA domain in RGA plays a regulatory role in GA-induced degradation of RGA. Deletion of this region stabilizes the rga-Delta 17 mutant protein, and regardless of the endogenous GA status rga-Delta 17 becomes a constitutively active repressor of GA signaling.

Amino Acid Motifs↗
PubMed2001

Synergistic derepression of gibberellin signaling by removing RGA and GAI function in Arabidopsis thaliana.

RGA and GAI are negative regulators of the gibberellin (GA) signal transduction pathway in Arabidopsis thaliana. These genes may have partially redundant functions because they are highly homologous, and plants containing single null mutations at these loci are phenotypically similar to wild type. Previously, rga loss-of-function mutations were shown to partially suppress defects of the GA-deficient ga1-3 mutant. Phenotypes rescued include abaxial trichome initiation, rosette radius, flowering time, stem elongation, and apical dominance. Here we present work showing that the rga-24 and gai-t6 null mutations have a synergistic effect on plant growth. Although gai-t6 alone has little effect, when combined with rga-24, they completely rescued the above defects of ga1-3 to wild-type or GA-overdose phenotype. However, seed germination and flower development defects were not restored. Additionally, rga-24 and rga-24/gai-t6 but not gai-t6 alone caused increased feedback inhibition of expression of a GA biosynthetic gene in both the ga1-3 and wild-type backgrounds. These results demonstrate that RGA and GAI have partially redundant functions in maintaining the repressive state of the GA-signaling pathway, but RGA plays a more dominant role than GAI. Removing both RGA and GAI function allows for complete derepression of many aspects of GA signaling.

Arabidopsis↗
PubMed2001

Repressing a repressor: gibberellin-induced rapid reduction of the RGA protein in Arabidopsis.

RGA (for repressor of ga1-3) and SPINDLY (SPY) are likely repressors of gibberellin (GA) signaling in Arabidopsis because the recessive rga and spy mutations partially suppressed the phenotype of the GA-deficient mutant ga1-3. We found that neither rga nor spy altered the GA levels in the wild-type or the ga1-3 background. However, expression of the GA biosynthetic gene GA4 was reduced 26% by the rga mutation, suggesting that partial derepression of the GA response pathway by rga resulted in the feedback inhibition of GA4 expression. The green fluorescent protein (GFP)-RGA fusion protein was localized to nuclei in transgenic Arabidopsis. This result supports the predicted function of RGA as a transcriptional regulator based on sequence analysis. Confocal microscopy and immunoblot analyses demonstrated that the levels of both the GFP-RGA fusion protein and endogenous RGA were reduced rapidly by GA treatment. Therefore, the GA signal appears to derepress the GA signaling pathway by degrading the repressor protein RGA. The effect of rga on GA4 gene expression and the effect of GA on RGA protein level allow us to identify part of the mechanism by which GA homeostasis is achieved.

Arabidopsis↗
PubMed1999

Molecular cloning of LMO41, a new human LIM domain gene.

We have identified a new human LIM domain gene by isolating an autoantigenic cDNA clone from a human breast tumor cDNA library. The predicted amino acid sequence of the cDNA clone's 495 bp open reading frame contains two tandem LIM domain motifs, and within the LIM domain region there is 62% identity with the analogous region of the LIM-only gene LMO1. The homology to LMO1 is restricted to the 360 bp region encoding the tandemly repeated LIM domains, the rest of the open reading frame as well as the extensive, GC-rich 5' untranslated region, and 3' region of the 2 kb cDNA sequence are unrelated to any known genes. This gene has been designated LMO4.

Adaptor Proteins, Signal Transducing↗
PubMed1997

A consecutive series of adults with brain injury treated with a washing and dressing retraining program.

OBJECTIVES: Single-case reports indicate that behavioral methods can assist persons with brain injury to redevelop self-care skills. However, the proportion of patients who could benefit from these interventions is unknown. The present study used a specific retraining protocol to treat all patients admitted to a single facility over a 3-year period who were unable to wash and dress independently. METHOD: Four patients out of 48 met the study criteria and were treated with the washing and dressing protocol. Three had traumatic brain injury, and one had brain injury after cerebral bleed. The training program involved behavioral observation, task analysis, consistent practice, and cue fading. The Adaptive Behavior Scale was used to measure behavior change. RESULTS: Three subjects achieved rapid independence in washing and dressing (20 days, 37 days, and 11 days of treatment), and one did not show significant clinical improvement. CONCLUSION: All patients admitted to the facility during a 3-year period who required washing and dressing retraining were treated with the same protocol. The consecutive series design prevented researchers from selecting patients who they believed were good treatment candidates; therefore, the findings support the general applicability of the training program.

Activities of Daily Living↗
PubMed1996

Cloning of a novel nucleolar guanosine 5'-triphosphate binding protein autoantigen from a breast tumor.

A cDNA clone encoding an immunoreactive autoantigen (Ngp-1) was isolated by screening lambda gt11 human ductal breast tumor expression libraries with autologous patient serum. The complete 2.3-kb nucleotide sequence of the cDNA was found to contain an open reading frame that could encode a protein of 731 amino acids. The predicted amino acid sequence contains a high concentration of charged amino acids in the carboxy terminal quarter of the molecule, three guanosine 5'-triphosphate (GTP)-binding protein motifs, and a consensus nuclear localization signal. The arrangement and spacing of the GTP-binding protein motifs indicate that Ngp-1 belongs to a newly described subfamily of GTPases. Except for the consensus motifs, neither nucleotide sequence, nor the predicted amino acid sequence of the Ngp-1 cDNA showed the slightest homology to any vertebrate gene product sequence listed in the databases. Northern blot analysis showed the 2.3-kb transcript to be ubiquitously expressed at relatively low levels in all human tissues tested, with the highest level of expression in the testes. Immunohistochemical analysis of tissue sections with affinity-purified antiserum raised against a recombinant Ngp-1 protein revealed that the antigen was exclusively localized to the nucleolus and nucleolar organizer regions in all cell types analyzed.

Amino Acid Sequence↗
PubMed1994

Institutional environments and organizational responses to AIDS.

Drawing from theory on institutionalized organizational environments, this paper analyzes the actions of community-based service programs providing care for people with AIDS. The focus is on the interorganizational relations developed by the lead agencies in demonstration projects attempting to coordinate services in three communities. The paper identifies differential styles of organizational response to developmental and operational issues. These differences are related to the conceptual distinction between organizational responses to technical environments and those to normative, or "institutional," environmental features. Various factors are identified that appear to promote a higher degree of institutionalization in interorganizational relations. Coordination as a reform strategy is seen to have become, in itself, an institutionalized myth to which organizations must subscribe in order to gain legitimacy.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Defining needs, defining systems: a critical analysis.

This article examines the model of need assessment commonly used in social service programs for older adults. Whereas this model defines need as an individual attribute, remediable through programmatic intervention, an alternative formulation suggests that organizational imperatives shape the definition of client need while obscuring their own role in the production of this information. A case study and historical analysis assess the roots of this process and its consequences for clients, staff, and aging programs.

Aged↗
PubMed1990

A comparison of hospital and community case management programs for persons with AIDS.

To determine whether locus of AIDS case management affects the content of this service, a survey of case managers in 42 major American cities was conducted. One hundred seventy-one case managers working in both public hospitals and community-based organizations (CBOs) responded. Hospital case managers were substantially more likely to report clinical training than CBO case managers. Hospital case managers' case loads were more likely to include drug users and patients with more urgent needs such as housing and drug abuse treatment. While CBO case managers were more likely to work to develop services in the community, hospital case managers reported working more closely with medical staff and discharge planning committees. CBO case managers reported greater difficulty obtaining a number of key services for their clients including home health care, housekeeping, and entitlements; hospital case managers reported greater difficulty obtaining emotional support volunteers. These results indicate that locus of case management strongly affects the structure and content of this service. The importance of these findings for future program planning is discussed.

Acquired Immunodeficiency Syndrome↗