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Biomedical subjects

S L Warren

Publications and source records attributed to S L Warren.

At least 19 recordsLinked to original sources
PubMed2001

pp60(c-src) modulates microvascular endothelial phenotype and in vitro angiogenesis.

The tyrosine kinase c-src associates with the platelet-derived growth factor (PDGF) receptor. Overexpression of wild-type c-src, a kinase-negative c-src mutant, and v-src in microvascular endothelial cells modulated the mitogenic effect of PDGF, suggesting that c-src kinase activity inhibits PDGF signals. Analyses of cell morphology in two-dimensional culture revealed changes in cell shape and size induced by the overexpression of c-src proteins. Investigations in three-dimensional culture unveiled a modulatory role of c-src during in vitro angiogenesis. Overexpression of c-src resulted in an increased diameter of tube-like structures, and the number of branching segments was decreased. Expression of the kinase-negative c-src mutant resulted in abortive tube formation consisting of disconnected multicellular fragments. These results indicate that the c-src tyrosine kinase exerts regulatory effects on endothelial proliferation, size, and cytoskeletal organization in two-dimensional culture and on the formation of a differentiated multicellular network in three-dimensional culture.

Adipose Tissue↗
PubMed2001

Assessment of anxiety in young children.

Anxiety disorders are highly prevalent and disabling conditions that can be identified in young children. Observations of infant temperament and attachment relationships have shown that certain early infant behaviors can be linked to later anxiety disorders. Research involving play narrative stories, pictures, cartoons, and puppets has demonstrated preliminary validity for new assessment methods of young children. Preliminary studies also have been conducted with new questionnaires and diagnostic interviews. Additional research is needed to refine these methods and to develop new comprehensive measures that focus specifically on different aspects of anxiety in young children.

Anxiety↗
PubMed2000

Internal representations: predicting anxiety from children's play narratives.

OBJECTIVE: This research uses children's story-stem play narratives to examine whether certain specified internal representations of self and experiences will predict later childhood anxiety. METHOD: Thirty-five nonclinical children were studied from 5 to 6 years of age. Narratives of the 5-year-old children were coded for negative expectations of self, others, and experiences. Parents and teachers completed the Child Behavior Checklist and Teacher's Report Form when the children were 5 and 6 years of age. Mothers completed the anxiety section of the Diagnostic Interview Schedule for Children when the children were 6 years of age. Parental anxiety and child temperament were also measured. RESULTS: Five-year-old child negative expectations significantly predicted mother/father/teacher reports of internalizing and anxiety symptoms and mother reports of separation anxiety, overanxious, and social phobia/avoidant disorder symptoms in the children at 6 years of age, even when anxiety and internalizing symptoms at 5 years of age were entered first in the regression equations. Child negative expectations predicted later anxiety in these analyses better than parental anxiety and child temperament. CONCLUSIONS: Child negative expectations may be a risk factor or a mechanism for the development of later anxiety. Children's narratives may be useful for examining such representations and identifying children at risk.

Anxiety↗
PubMed1999

Behavioral genetic analyses of self-reported anxiety at 7 years of age.

OBJECTIVE: To conduct behavioral genetic analyses of self-reported childhood anxiety at 7 years of age. METHOD: Three hundred twenty-six same-sex twin pairs (174 monozygotic, 152 dizygotic) completed the Revised Children's Manifest Anxiety Scale at 7 years of age. Behavioral genetic analyses were conducted on the total and subscale scores. RESULTS: Monozygotic within-pair correlations were higher than dizygotic correlations for physiological and social anxiety symptoms, suggesting heritable influences on these aspects. These results were found to be statistically significant with structural equation modeling. CONCLUSION: Certain symptoms of self-reported anxiety in children 7 years of age seem to result, at least in part, from genetic factors. Physiological and social anxiety symptoms, which may be related to behavioral inhibition, appear to be genetically influenced. These results are linked to previous findings in older children and adults.

Anxiety Disorders↗
PubMed1998

Ultraviolet radiation-induced ubiquitination and proteasomal degradation of the large subunit of RNA polymerase II. Implications for transcription-coupled DNA repair.

We have shown previously that UV radiation and other DNA-damaging agents induce the ubiquitination of a portion of the RNA polymerase II large subunit (Pol II LS). In the present study UV irradiation of repair-competent fibroblasts induced a transient reduction of the Pol II LS level; new protein synthesis restored Pol II LS to the base-line level within 16-24 h. In repair-deficient xeroderma pigmentosum cells, UV radiation-induced ubiquitination of Pol II LS was followed by a sustained reduction of Pol II LS level. In both normal and xeroderma pigmentosum cells, the ubiquitinated Pol II LS had a hyperphosphorylated COOH-terminal domain (CTD), which is characteristic of elongating Pol II. The portion of Pol II LS whose steady-state level diminished most quickly had a relatively hypophosphorylated CTD. The ubiquitinated residues did not map to the CTD. Importantly, UV-induced reduction of Pol II LS level in repair-competent or -deficient cells was inhibited by the proteasome inhibitors lactacystin or MG132. These data demonstrate that UV-induced ubiquitination of Pol II LS is followed by its degradation in the proteasome. These results suggest, contrary to a current model of transcription-coupled DNA repair, that elongating Pol II complexes which arrest at intragenic DNA lesions may be aborted rather than resuming elongation after repair takes place.

Cell Line↗
PubMed1998

Growth-related changes in phosphorylation of yeast RNA polymerase II.

The largest subunit of RNA polymerase II contains a unique C-terminal domain (CTD) consisting of tandem repeats of the consensus heptapeptide sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7. Two forms of the largest subunit can be separated by SDS-polyacrylamide gel electrophoresis. The faster migrating form termed IIA contains little or no phosphate on the CTD, whereas the slower migrating II0 form is multiply phosphorylated. CTD kinases with different phosphoryl acceptor specificities are able to convert IIA to II0 in vitro, and different phosphoisomers have been identified in vivo. In this paper we report the binding specificities of a set of monoclonal antibodies that recognize different phosphoepitopes on the CTD. Monoclonal antibodies like H5 recognize phosphoserine in position 2, whereas monoclonal antibodies like H14 recognize phosphoserine in position 5. The relative abundance of these phosphoepitopes changes when growing yeast enter stationary phase or are heat-shocked. These results indicate that phosphorylation of different CTD phosphoacceptor sites are independently regulated in response to environmental signals.

Amino Acid Sequence↗
PubMed1997

Dynamic relocation of transcription and splicing factors dependent upon transcriptional activity.

Recent interest in understanding the spatial organization of gene expression has focused attention on nuclear structures known as speckles or interchromatin granule clusters (IGCs) revealed by immunofluorescence or electron microscopy. Staining of nuclear factors involved in pre-mRNA splicing or, more recently, transcription, reveals 20-40 speckles per nucleus, resulting in the intriguing suggestion that speckles are nuclear sites of transcription and processing. In contrast, other investigations have observed transcription in other areas of the nucleus. In this study, we have examined the localization of active transcription as detected by uridine incorporation and recently developed RNA polymerase II antibodies, and compared this pattern with that of known splicing and polyadenylation factors. Our results indicate that in actively transcribing cells, transcription and splicing factors are dispersed throughout the nucleus with abundant sites of preferred localization. In contrast, in poorly transcribing cells, polymerase II and splicing factors localize to speckles. In nuclei inactivated for transcription by drugs or heat shock, the speckle type of co-localization is accentuated. These observations suggest that bulk transcription and splicing occur throughout the nucleus during periods of active transcription; and that factors involved in these two processes re-locate to minimal speckle domains during periods of inactive transcription.

Animals↗
PubMed1997

Splicing factors associate with hyperphosphorylated RNA polymerase II in the absence of pre-mRNA.

The carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II (Pol II) contains multiple tandem copies of the consensus heptapeptide, TyrSerProThrSerProSer. Concomitant with transcription initiation the CTD is phosphorylated. Elongating polymerase has a hyperphosphorylated CTD, but the role of this modification is poorly understood. A recent study revealed that some hyperphosphorylated polymerase molecules (Pol IIo) are nonchromosomal, and hence transcriptionally unengaged (Bregman, D.B., L. Du, S. van der Zee, S.L. Warren. 1995. J. Cell Biol. 129: 287-298). Pol IIo was concentrated in discrete splicing factor domains, suggesting a possible relationship between CTD phosphorylation and splicing factors, but no evidence beyond immunolocalization data was provided to support this idea. Here, we show that Pol IIo co-immunoprecipitates with members of two classes of splicing factors, the Sm snRNPs and non-snRNP SerArg (SR) family proteins. Significantly, Pol IIo's association with splicing factors is maintained in the absence of pre-mRNA, and the polymerase need not be transcriptionally engaged. We also provide definitive evidence that hyperphosphorylation of Pol II's CTD is poorly correlated with its transcriptional activity. Using monoclonal antibodies (mAbs) H5 and H14, which are shown here to recognize phosphoepitopes on Pol II's CTD, we have quantitated the level of Pol IIo at different stages of the cell cycle. The level of Pol IIo is similar in interphase and mitotic cells, which are transcriptionally active and inactive, respectively. Finally, complexes containing Pol IIo and splicing factors can be prepared from mitotic as well as interphase cells. The experiments reported here establish that hyperphosphorylation of the CTD is a good indicator of polymerase's association with snRNP and SR splicing factors, but not of its transcriptional activity. Most importantly, the present study suggests that splicing factors may associate with the polymerase via the hyperphosphorylated CTD.

Cell Cycle↗
PubMed1997

A functional interaction between the carboxy-terminal domain of RNA polymerase II and pre-mRNA splicing.

In the preceding study we found that Sm snRNPs and SerArg (SR) family proteins co-immunoprecipitate with Pol II molecules containing a hyperphosphorylated CTD (Kim et al., 1997). The association between Pol IIo and splicing factors is maintained in the absence of pre-mRNA, and the polymerase need not be transcriptionally engaged (Kim et al., 1997). The latter findings led us to hypothesize that a phosphorylated form of the CTD interacts with pre-mRNA splicing components in vivo. To test this idea, a nested set of CTD-derived proteins was assayed for the ability to alter the nuclear distribution of splicing factors, and to interfere with splicing in vivo. Proteins containing heptapeptides 1-52 (CTD52), 1-32 (CTD32), 1-26 (CTD26), 1-13 (CTD13), 1-6 (CTD6), 1-3 (CTD3), or 1 (CTD1) were expressed in mammalian cells. The CTD-derived proteins become phosphorylated in vivo, and accumulate in the nucleus even though they lack a conventional nuclear localization signal. CTD52 induces a selective reorganization of splicing factors from discrete nuclear domains to the diffuse nucleoplasm, and significantly, it blocks the accumulation of spliced, but not unspliced, human beta-globin transcripts. The extent of splicing factor disruption, and the degree of inhibition of splicing, are proportional to the number of heptapeptides added to the protein. The above results indicate a functional interaction between Pol II's CTD and pre-mRNA splicing.

Amino Acid Sequence↗
PubMed1997

Child and adolescent anxiety disorders and early attachment.

OBJECTIVE: The major aim of this research is to determine whether infants who were anxiously/resistantly attached in infancy develop more anxiety disorders during childhood and adolescence than infants who were securely attached. To test different theories of anxiety disorders, newborn temperament and maternal anxiety were included in multiple regression analyses. METHOD: Infants participated in Ainsworth's Strange Situation Procedure at 12 months of age. The Schedule for Affective Disorders and Schizophrenia for School-Age Children was administered to the 172 children when they reached 17.5 years of age. Maternal anxiety and infant temperament were assessed near the time of birth. RESULTS: The hypothesized relation between anxious/resistant attachment and later anxiety disorders was confirmed. No relations with maternal anxiety and the variables indexing temperament were discovered, except for a composite score of nurses' ratings designed to access "high reactivity," and the Neonatal Behavioral Assessment Scale clusters of newborn range of state and inability to habituate to stimuli. Anxious/resistant attachment continued to significantly predict child/adolescent anxiety disorders, even when entered last, after maternal anxiety and temperament, in multiple regression analyses. CONCLUSION: The attachment relationship appears to play an important role in the development of anxiety disorders. Newborn temperament may also contribute.

Anxiety Disorders↗
PubMed1997

Identification of transcription factories in nuclei of HeLa cells transiently expressing the Us11 gene of herpes simplex virus type 1.

Nuclear distribution and migration of herpes simplex virus type 1 Us11 transcripts were studied in transient expression at the ultrastructural level and compared to that of RNA polymerase II protein. Transcription was monitored by autoradiography following a short pulse with tritiated uridine. Us11 transcripts accumulated mainly over the foci of intermingled RNP fibrils as demonstrated by the presence of silver grains localizing incorporated radioactive uridine superimposed to these structures in which the presence of Us11 RNA and poly(A) tails was previously demonstrated. Silver grains were also scattered over the remaining nucleoplasm but not in the clusters of interchromatin granules, and over the dense fibrillar component of the nucleolus as in control, nontransfected HeLa cells. Pulse-chase experiments revealed the transient presence of migrating RNA in the clusters of interchromatin granules. RNA polymerase II was revealed by immunogold labeling following the use of two monoclonal antibodies: mAb H5, which recognizes the hyperphosphorylated form of the carboxy-terminal domain (CTD) of the molecule, and mAb 7C2, which recognizes both its hyperphosphorylated and unphosphorylated forms. The two mAbs bind to the newly formed Us11 transcription factories and the clusters of interchromatin granules of transfected cells. In control cells, however, clusters of interchromatin granules were labeled with mAb H5 but not with mAB 7C2. Taken together, our data demonstrate the involvement of the clusters of interchromatin granules in the intranuclear migration of Us11 RNA in transient expression. They also suggest the occurrence of changes in the accessibility of the RNA polymerase II CTD upon expression of the Us11 gene after transfection by exposing some epitopes, otherwise masked in nontransfected cells.

Cell Nucleus↗
PubMed1996

UV-induced ubiquitination of RNA polymerase II: a novel modification deficient in Cockayne syndrome cells.

Damage to actively transcribed DNA is preferentially repaired by the transcription-coupled repair (TCR) system. TCR requires RNA polymerase II (Pol II), but the mechanism by which repair enzymes preferentially recognize and repair DNA lesions on Pol II-transcribed genes is incompletely understood. Herein we demonstrate that a fraction of the large subunit of Pol II (Pol II LS) is ubiquitinated after exposing cells to UV-radiation or cisplatin but not several other DNA damaging agents. This novel covalent modification of Pol II LS occurs within 15 min of exposing cells to UV-radiation and persists for about 8-12 hr. Ubiquitinated Pol II LS is also phosphorylated on the C-terminal domain. UV-induced ubiquitination of Pol II LS is deficient in fibroblasts from individuals with two forms of Cockayne syndrome (CS-A and CS-B), a rare disorder in which TCR is disrupted. UV-induced ubiquitination of Pol II LS can be restored by introducing cDNA constructs encoding the CSA or CSB genes, respectively, into CS-A or CS-B fibroblasts. These results suggest that ubiquitination of Pol II LS plays a role in the recognition and/or repair of damage to actively transcribed genes. Alternatively, these findings may reflect a role played by the CSA and CSB gene products in transcription.

Cell Line↗
PubMed1996

A hyperphosphorylated form of the large subunit of RNA polymerase II is associated with splicing complexes and the nuclear matrix.

A hyperphosphorylated form of the largest subunit of RNA polymerase II (pol IIo) is associated with the pre-mRNA splicing process. Pol IIo was detected in association with a subset of small nuclear ribonucleoprotein particle and Ser-Arg protein splicing factors and also with pre-mRNA splicing complexes assembled in vitro. A subpopulation of pol IIo was localized to nuclear "speckle" domains enriched in splicing factors, indicating that it may also be associated with RNA processing in vivo. Moreover, pol IIo was retained in a similar pattern following in situ extraction of cells and was quantitatively recovered in the nuclear matrix fraction. The results implicate nuclear matrix-associated hyperphosphorylated pol IIo as a possible link in the coordination of transcription and splicing processes.

Animals↗
PubMed1996

Can emotions and themes in children's play predict behavior problems?

OBJECTIVE: To empirically test whether systematic examination of emotions and themes in children's play can provide useful information about childhood problems. METHOD: Using the MacArthur Story-Stem Battery and coding system, distress and destructive themes (aggression, personal injury, and atypical negative responses) were coded from the play of 51 children at ages 3, 4, and 5 years, in a low-risk, nonclinical volunteer sample. To measure behavior problems, both parents completed the Child Behavior Checklist at all ages, and teachers completed the Teacher's Report Form when the children reached 5 years of age. RESULTS: Both distress and destructive themes in the play of 4- and 5-year-olds were found to correlate with externalizing behavior problems as rated by parents and teachers. CONCLUSIONS: Children who display more distress during play at 4 and 5 years of age and who demonstrate destructive themes at 4 and 5 years of age appear to have more externalizing behavior problems, as rated by their parents and teachers. These results provide empirical support for the use of play as an assessment tool in young children. The findings suggest approaches to and limitations of play interpretation.

Child Behavior Disorders↗
PubMed1995

Transcription-dependent redistribution of the large subunit of RNA polymerase II to discrete nuclear domains.

A subpopulation of the largest subunit of RNA polymerase II (Pol II LS) is located in 20-50 discrete subnuclear domains that are closely linked to speckle domains, which store splicing proteins. The speckle-associated fraction of Pol II LS is hyperphosphorylated on the COOH-terminal domain (CTD), and it is highly resistant to extraction by detergents. A diffuse nucleoplasmic fraction of Pol II LS is relatively hypophosphorylated on the CTD, and it is easily extracted by detergents. In transcriptionally active nuclei, speckle bound hyperphosphorylated Pol II LS molecules are distributed in irregularly shaped speckle domains, which appear to be interconnected via a reticular network. When transcription is inhibited, hyperphosphorylated Pol II LS and splicing protein SC35 accumulate in speckle domains, which are transformed into enlarged, dot-like structures lacking interconnections. When cells are released from transcriptional inhibition, Pol IIO and SC35 redistribute back to the interconnected speckle pattern of transcriptionally active cells. The redistribution of Pol II and SC35 is synchronous, reversible, and temperature dependent. It is concluded that: (a) hyperphosphorylation of Pol II LS's CTD is a better indicator of its tight association to discrete subnuclear domains than its transcriptional activity; (b) during states of transcriptional inhibition, hyperphosphorylated Pol II LS can be stored in enlarged speckle domains, which under the light microscope appear to coincide with the storage sites for splicing proteins; and (c) Pol II and splicing proteins redistribute simultaneously according to the overall transcriptional activity of the nucleus.

Amanitins↗
PubMed1995

Specialty nursing council: a coalition of advanced practice nurses.

Advanced practice nurses (APNs) are often isolated within their specialty area, placing unnecessary limits on their range of influence and making professional networking more difficult. Networking and sharing of information are critical to developing a broadened perspective. As APNs become more systems and program oriented, a strong affiliation base must be maintained. How a group of APNs in one hospital developed a coalition to decrease the isolation gap, promote sharing of information and encourage cohesiveness is discussed in this article. The process of moving from the rather narrowed perspective of individual practice to the concept of group unity and collaboration is explored.

Education, Nursing, Continuing↗
PubMed1994

Cytostellin distributes to nuclear regions enriched with splicing factors.

Cytostellin, a approximately 240 kDa phosphoprotein found in all cells examined from human to yeast, is predominantly intranuclear in interphase mammalian cells and undergoes continuous redistribution during the cell cycle. Here, mammalian cytostellin is shown to localize to intranuclear regions enriched with multiple splicing proteins, including spliceosome assembly factor, SC-35. Cytostellin and the splicing proteins also co-localize to discrete foci (called 'dots'), which are distributed throughout the cell during mitosis and part of G1. The cytostellin that is localized to these dots resists extraction by Triton X-100, indicating that it is tightly associated with insoluble cell structures. All immunostainable cytostellin reappears in the nucleus before S-phase. Although cytostellin and the splicing proteins co-localize in interphase and dividing cells, cytostellin is not detected in purified spliceosomes, and it associates with six unidentified proteins, forming a macromolecular complex that is biochemically distinct from the proteins that comprise spliceosomes. This macromolecular complex is detected at constant levels throughout the cell cycle, and the level of cytostellin protein remains constant during the cell cycle. Nevertheless, intranuclear cytostellin immunostaining fluctuates markedly during the cell cycle. The monoclonal antibody (mAb) H5 epitope of cytostellin is 'masked' in serum-starved cells, but 60 minutes after serum stimulation intense cytostellin immunoreactivity appears in the nuclear speckles. This rapid induction of cytostellin immunoreactivity in subnuclear regions enriched with many splicing factors, as well as accumulations of RNA polymerase II (Pol II) transcripts, suggests that cytostellin may have a function related to mRNA biogenesis.

Animals↗