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Full-Text Articles in Life Sciences
A Gene Expression Screen Identifies Earli1 As A Novel Vernalization-Responsive Gene In Arabidopsis Thaliana, Richard K. Wilkosz, Michael Schläppi
A Gene Expression Screen Identifies Earli1 As A Novel Vernalization-Responsive Gene In Arabidopsis Thaliana, Richard K. Wilkosz, Michael Schläppi
Biological Sciences Faculty Research and Publications
Vernalization promotes early flowering in late ecotypes of Arabidopsis thaliana. The mechanisms of vernalization are poorly understood. A subtractive hybridization approach was used to isolate vernalization-responsive genes from a late-flowering ecotype of Arabidopsis thaliana based on the premise that transcript levels of such genes would increase with cold treatment and remain high even after removal of the vernalization stimulus. EARLI1 is the first Arabidopsis gene shown to be stably activated by vernalization. The abundance of its RNA is progressively elevated by vernalization and remains high for at least 20 days at room temperature. The basal level of EARLI1 RNA …
Selection Of Alternative 5′ Splice Sites: Role Of U1 Snrnp And Models For The Antagonistic Effects Of Sf2/Asf And Hnrnp A1, Ian C. Eperon, Olga V. Makarova, Akila Mayeda, Stephen Munroe, Javier F. Cáceres, Daniel G. Hayward, Adrian R. Krainer
Selection Of Alternative 5′ Splice Sites: Role Of U1 Snrnp And Models For The Antagonistic Effects Of Sf2/Asf And Hnrnp A1, Ian C. Eperon, Olga V. Makarova, Akila Mayeda, Stephen Munroe, Javier F. Cáceres, Daniel G. Hayward, Adrian R. Krainer
Biological Sciences Faculty Research and Publications
The first component known to recognize and discriminate among potential 5′ splice sites (5′SSs) in pre-mRNA is the U1 snRNP. However, the relative levels of U1 snRNP binding to alternative 5′SSs do not necessarily determine the splicing outcome. Strikingly, SF2/ASF, one of the essential SR protein-splicing factors, causes a dose-dependent shift in splicing to a downstream (intron-proximal) site, and yet it increases U1 snRNP binding at upstream and downstream sites simultaneously. We show here that hnRNP A1, which shifts splicing towards an upstream 5′SS, causes reduced U1 snRNP binding at both sites. Nonetheless, the importance of U1 snRNP binding is …
A Family Of Developmentally Excised Dna Elements In Tetrahymena Is Under Selective Pressure To Maintain An Open Reading Frame Encoding An Integrase-Like Protein, Jill A. Gershan, Kathleen M. Karrer
A Family Of Developmentally Excised Dna Elements In Tetrahymena Is Under Selective Pressure To Maintain An Open Reading Frame Encoding An Integrase-Like Protein, Jill A. Gershan, Kathleen M. Karrer
Biological Sciences Faculty Research and Publications
Tlr1 is a member of a family of ~20-30 DNA elements that undergo developmentally regulated excision during formation of the macronucleus in the ciliated protozoan Tetrahymena. Analysis of sequence internal to the right boundary of Tlr1 revealed the presence of a 2 kb open reading frame (ORF) encoding a deduced protein with similarity to retrotransposon integrases. The ORFs of five unique clones were sequenced. The ORFs have 98% sequence conservation and align without frameshifts, although one has an additional trinucleotide at codon 561. Nucleotide changes among the five clones are highly non-random with respect to the position in the …
Varying The Abundance Of O Antigen In Rhizobium Etli And Its Effect On Symbiosis With Phaseolus Vulgaris, K. Dale Noel, Lennart Scott Forsberg, Russell W. Carlson
Varying The Abundance Of O Antigen In Rhizobium Etli And Its Effect On Symbiosis With Phaseolus Vulgaris, K. Dale Noel, Lennart Scott Forsberg, Russell W. Carlson
Biological Sciences Faculty Research and Publications
Judged by migration of its lipopolysaccharide (LPS) in gel electrophoresis, the O antigen of Rhizobium etli mutant strain CE166 was apparently of normal size. However, its LPS sugar composition and staining of the LPS bands after electrophoresis indicated that the proportion of its LPS molecules that possessed O antigen was only 40% of the wild-type value. Its LPS also differed from the wild type by lacking quinovosamine (2-amino-2,6-dideoxyglucose). Both of these defects were due to a single genetic locus carrying a Tn5 insertion. The deficiency in O-antigen amount, but not the absence of quinovosamine, was suppressed by transferring into …
Have We Forgotten The Forest Because Of The Trees?, Stefan A. Schnitzer, Walter P. Carson
Have We Forgotten The Forest Because Of The Trees?, Stefan A. Schnitzer, Walter P. Carson
Biological Sciences Faculty Research and Publications
No abstract provided.
The Impact Of Lianas On Tree Regeneration In Tropical Forest Canopy Gaps: Evidence For An Alternative Pathway Of Gap‐Phase Regeneration, Stefan A. Schnitzer, James W. Dalling, Walter P. Carson
The Impact Of Lianas On Tree Regeneration In Tropical Forest Canopy Gaps: Evidence For An Alternative Pathway Of Gap‐Phase Regeneration, Stefan A. Schnitzer, James W. Dalling, Walter P. Carson
Biological Sciences Faculty Research and Publications
1 Regeneration in forest canopy gaps is thought to lead invariably to the rapid recruitment and growth of trees and the redevelopment of the canopy. Our observations, however, suggest that an alternate successional pathway is also likely, whereby gap‐phase regeneration is dominated by lianas and stalled in a low‐canopy state for many years. We investigated gap‐phase regeneration in an old‐growth tropical forest on Barro Colorado Island (BCI) in Panama to test the following two hypotheses: (i) many gaps follow a pathway in which they remain at a low canopy height and are dominated by lianas and (ii) the paucity of …
Physiology Of A Microgravity Environment Invited Review: Microgravity And Skeletal Muscle, Robert H. Fitts, Danny R. Riley, Jeffrey J. Widrick
Physiology Of A Microgravity Environment Invited Review: Microgravity And Skeletal Muscle, Robert H. Fitts, Danny R. Riley, Jeffrey J. Widrick
Biological Sciences Faculty Research and Publications
Spaceflight (SF) has been shown to cause skeletal muscle atrophy; a loss in force and power; and, in the first few weeks, a preferential atrophy of extensors over flexors. The atrophy primarily results from a reduced protein synthesis that is likely triggered by the removal of the antigravity load. Contractile proteins are lost out of proportion to other cellular proteins, and the actin thin filament is lost disproportionately to the myosin thick filament. The decline in contractile protein explains the decrease in force per cross-sectional area, whereas the thin-filament loss may explain the observed postflight increase in the maximal velocity …
Uncharged Trna Activates Gcn2 By Displacing The Protein Kinase Moiety From A Bipartite Trna-Binding Domain, Jinsheng Dong, Hongfang Qiu, Minerva Garcia-Barrio, James T. Anderson, Alan G. Hinnebusch
Uncharged Trna Activates Gcn2 By Displacing The Protein Kinase Moiety From A Bipartite Trna-Binding Domain, Jinsheng Dong, Hongfang Qiu, Minerva Garcia-Barrio, James T. Anderson, Alan G. Hinnebusch
Biological Sciences Faculty Research and Publications
Protein kinase GCN2 regulates translation in amino acid–starved cells by phosphorylating eIF2. GCN2 contains a regulatory domain related to histidyl-tRNA synthetase (HisRS) postulated to bind multiple deacylated tRNAs as a general sensor of starvation. In accordance with this model, GCN2 bound several deacylated tRNAs with similar affinities, and aminoacylation of tRNAPhe weakened its interaction with GCN2. Unexpectedly, the C-terminal ribosome binding segment of GCN2 (C-term) was required in addition to the HisRS domain for strong tRNA binding. A combined HisRS+C-term segment bound to the isolated protein kinase (PK) domain in vitro, and tRNA impeded this interaction. An activating mutation …
A Developmentally Regulated Deletion Element With Long Terminal Repeats Has Cis-Acting Sequences In The Flanking Dna, Namrata S. Patil, Kathleen M. Karrer
A Developmentally Regulated Deletion Element With Long Terminal Repeats Has Cis-Acting Sequences In The Flanking Dna, Namrata S. Patil, Kathleen M. Karrer
Biological Sciences Faculty Research and Publications
Approximately 6000 specific DNA deletion events occur during development of the somatic macronucleus of the ciliate Tetrahymena. The eliminated Tlr1 element is 13 kb or more in length and has an 825 bp inverted repeat near the rearrangement junctions. A functional analysis of the cis-acting sequences required for Tlr1 rearrangement was performed. A construct consisting of the entire inverted repeat and several hundred base pairs of flanking DNA on each side was rearranged accurately in vivo and displayed junctional variability similar to the chromosomal Tlr1 rearrangement. Thus, 11 kb or more of internal element DNA is not required …
Effect Of Spaceflight On The Maximal Shortening Velocity, Morphology, And Enzyme Profile Of Fast- And Slow-Twitch Skeletal Muscle Fibers In Rhesus Monkeys, Robert Fitts, Janell Romatowski, Lourdes De La Cruz, Jeffrey J. Widrick, Dominique Desplanches
Effect Of Spaceflight On The Maximal Shortening Velocity, Morphology, And Enzyme Profile Of Fast- And Slow-Twitch Skeletal Muscle Fibers In Rhesus Monkeys, Robert Fitts, Janell Romatowski, Lourdes De La Cruz, Jeffrey J. Widrick, Dominique Desplanches
Biological Sciences Faculty Research and Publications
No abstract provided.
Effect Of Spaceflight On The Isotonic Contractile Properties Of Single Skeletal Muscle Fibers In The Rhesus Monkey, Robert Fitts, Janell Romatowski, Cynthia A. Blaser, Lourdes De La Cruz, Gwen J. Gettelman, Jeffrey J. Widrick
Effect Of Spaceflight On The Isotonic Contractile Properties Of Single Skeletal Muscle Fibers In The Rhesus Monkey, Robert Fitts, Janell Romatowski, Cynthia A. Blaser, Lourdes De La Cruz, Gwen J. Gettelman, Jeffrey J. Widrick
Biological Sciences Faculty Research and Publications
No abstract provided.