Heat shock affects cell cycling in the neural plate of cultured rat embryos: A flow cytometric study

Walsh, David A.; Morris, Valerie B.

doi:10.1002/tera.1420400606

Cited by 31 publications

(10 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was also the finding by other labs that heat shocked embryos in culture (Mirkes, 1985;Walsh et al, 1987). As observed in vivo, these effects were time-and temperature-dependent (Walsh and Morris, 1989;Breen et al, 1999). Therefore, the cell death that was observed was the predominate effect of heat in embryos in vitro and in vivo.…”

Section: Mechanistic Observationssupporting

confidence: 81%

Hyperthermia: malformations to chaperones

Bennett

2010

Birth Defects Research Pt B

View full text Add to dashboard Cite

Hyperthermia has been known to induce malformations in numerous animal models as well being associated with human abnormalities. This was apparent particularly when the hyperthermia exposure was during the early stages of neural development. Although it was recognized relatively early that these exposures induced cell death, the specific molecular mechanism of how a brief heat exposure was translated in to specific cellular functions remains largely unknown. While our understanding of the events that govern how cells react to heat, or stresses in general, has increased, there is much that remains undiscovered. In this brief review, animal and clinical observations are outlined as are some of the scientific explorations that were undertaken to characterize, define, and better understand the morphological, biochemical, and molecular effects of hyperthermia on the developing embryo.

show abstract

Section: Mechanistic Observationssupporting

confidence: 81%

Hyperthermia: malformations to chaperones

Bennett

2010

Birth Defects Research Pt B

View full text Add to dashboard Cite

show abstract

“…After heat shock, DNA synthesis has been shown to be reduced. In mammalian cells a short heat shock is sufficient to arrest cell division at S phase (37). It (38), one of which is in the region of the histone genes (region 39D).…”

Section: Discussionmentioning

confidence: 99%

Rapid changes in Drosophila transcription after an instantaneous heat shock.

1993

View full text Add to dashboard Cite

Heat shock rapidly activates expression of some genes and represses others. The kinetics of changes in RNA polymerase distribution on heat shock-modulated genes provides a framework for evaluating the mechanisms of activation and repression of transcription. Here, using two methods, we examined the changes in RNA polymerase II association on a set of Drosophila genes at 30-s intervals following an instantaneous heat shock. In the first method, Drosophila Schneider line 2 cells were quickly frozen to halt transcription, and polymerase distribution was analyzed by a nuclear run-on assay. RNA polymerase transcription at the 5' end of the hsp7O gene could be detected within 30 to 60 s of induction, and by 120 s the first wave of polymerase could already be detected near the 3' end of the gene. A similar rapid induction was found for the small heat shock genes (hsp22, hsp23, hsp26, and hsp27). In contrast to this rapid activation, transcription of the histone Hi gene was found to be rapidly repressed, with transcription reduced by -90%o within 300 s of heat shock. Similar results were obtained by an in vivo UV cross-linking assay. In this second method, cell samples removed at 30-s intervals were irradiated with 40-,us bursts of UV light from a Xenon flash lamp, and the distribution of polymerase was examined by precipitating UV cross-linked protein-DNA complexes with an antibody to RNA polymerase II. Both approaches also showed the in vivo rate of movement of the first wave of RNA polymerase through the hsp7O gene to be -1.2 kb/min.Transcriptional activation of Drosophila heat shock genes can occur within minutes of exposure to a heat shock stimulus. It was previously found that within 2 min of exposing Drosophila larvae to a temperature of 37°C a distinct puff could be seen at cytological position 63B (which contains the heat shock gene hsp83) and that this puff reached its maximum size within 5 min (1). Incorporation of [3H]uridine was also found at the 87A and 87C loci (which together contain five copies of the hsp70 gene) within 1 min of heat shock (1), suggesting a rapid transcriptional response. In support of this finding, mRNA transcribed from the hsp70 gene can be detected as early as 4 min after shifting Schneider line 2 (SL2) cells to the full heat shock temperature, and an increase in the level of HSP70 can be detected as early as 8 to 12 min after heat shock (19). 46 bases (9,26,28). This polymerase presumably resumes elongation into the body of the gene once the promoter becomes activated. Pausing of polymerase has also been detected at the 5' ends of the hsp26 (9, 26, 29), hsp23 (25), and hsp27 genes (26). A promoter that already contains an initiated polymerase could be capable of responding very rapidly to an increase in temperature. To measure the rapidity of this response, SL2 cells were exposed to an instantaneous heat shock (by adding an equal volume of 56°C tissue culture medium), samples were removed at 30-s intervals, and then they were rapidly frozen in liquid nitrogen. After isolation of the...

show abstract

“…This exposure in vivo causes microphthalmia in 100% of surviving embryos [9]. In their flow cytometry studies, Walsh and Morris [85] also found that the heat stressed neurectodermal cells caused a partial synchronisation of the generation cycle by causing cells to accumulate for 1-2 h at the G1-S boundaries after treatments of 42, 43 or 42/43°C. Following treatments of 42 or 42/43°C there was also a barrier to cell progression at the S-G2 boundary.…”

Section: Apoptosis Following Heat Shockmentioning

confidence: 97%

“…However, in some cases, cell division is tightly controlled even though cells adopt fates independently of their lineage history. Using flow cytometry, Walsh and Morris [85] and Walsh et al [74] studied cell cycle changes and regulation and expression levels of hsp27, 71, 73 and 90 mRNA at various stages of the neurectodermal cell generation cycle and the effects of the various heat shock regimes ( fig. 3).…”

Section: Reviewsmentioning

confidence: 99%

Heat shock and the role of the HSPs during neural plate induction in early mammalian CNS and brain development

Walsh¹,

Li²,

Wu³

et al. 1997

CMLS, Cell. mol. life. sci.

View full text Add to dashboard Cite

We have investigated the early development expressional of the heat shock protein genes (hsps) and HSP synthesis and their role during neuroectoderm induction, differentiation and early CNS formation. The expression and kinetics of 90, 73/71, 47 and 27 HSPs on neuroectoderm differentiation was compared under normal and stressed conditions. The role of HSPs on neuroctoderm cell fate including thermotolerance and apoptosis using a whole in vitro embryo culture system was studied. Hsp expression appears closely linked in early mammalian development to critical differentiation and proliferation stages in early brain and heart formation. The hsps are developmentally activated around blastula stage and HSPs are constitutively expressed at high levels during neural tube closure and are heat shock responsive. Using both Northern analysis, confocal microscopy and whole mount in situ hybridisation we have identified the mRNA hsp transcripts and HSPs during organogenesis. HSPs were detected during neuroectoderm cell induction and differentiation with the hsp mRNA being tightly regulated during the cell cycle of neuroectoderm especially at early fore-, mid-, hindbrain and heart formation. The 'chaperone' functions of the HSPs are well known, recently during gastrulation the HSP47 and 27 have been shown to specifically bind and fold to nascent collagen and actin molecules respectively. This role is essential for the formation of the basement membrane, extra cellular matrix and neural crest migration during neural plate development. HSP function was observed by using anti-sense strategy, short '5 anti-sense cDNA' hsp oligonucleotides inhibited hsp expression during gastrulation in the whole embryo cultures. The developmental activation of the heat shock element (HSE) is essential to our understanding of the HSPs role in neuronal cell fate. Using specific polyclonal antibodies to HSF1 and 2 (Dr Nakai, Kyoto University) the expression of heat shock factors (HSFs) during neuroectoderm differentiation was examined. Using Western analysis, confocal microscopy and flow cytometry HSF1 and 2 were identified and studied under both normal and heat shocked conditions. During gastrulation higher levels of HSF1 and 2 were identified in the neuroectoderm layer especially in regions of the fore-, mid- and hindbrain. The heat shock response and activation of the HSPs 90, 70, 47 and 27 families have been correlated with HSF1 and 2. The HSF1 appears to be present in all early embryonic cells but appears not to bind to the HSE until early head fold stage at gastrulation when the presence of HSF2 is observed. During neuroectoderm differentiation the activation of HSF1 and 2 appears to correlate with high constitutive expression of many of the hsps specifically hsp90, 73, 71, 47 and 27 being tightly regulated by the cell cycle at neurulation.

show abstract

Heat shock affects cell cycling in the neural plate of cultured rat embryos: A flow cytometric study

Cited by 31 publications

References 13 publications

Hyperthermia: malformations to chaperones

Hyperthermia: malformations to chaperones

Rapid changes in Drosophila transcription after an instantaneous heat shock.

Heat shock and the role of the HSPs during neural plate induction in early mammalian CNS and brain development

Contact Info

Product

Resources

About