Overexpression of the transcription factor Rst2 inSchizosaccharomyces pombeindicates growth defect, mitotic defects, and microtubule disorder

Abstract

In Schizosaccharomyces pombe, the transcription factor Rst2 regulates ste11 in meiosis and fbp1 in glucogenesis downstream of the cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) pathway. Here, we demonstrate that Rst2 regulates additional cellular events. Overexpressed Rst2 elevated the frequency of oval, bent, branched, septated, and multi-septated cells. Cells showed normal nuclear divisions but exhibited abnormal nuclear organization at low frequency. In oval cells, microtubules were curved but they were rescued by the deletion of mal3. Since growth defect was not rescued by mal3 deletion, we argue that it is regulated independently. Loss of functional Pka1 exaggerated growth defect upon Rst2 overexpression because its downregulation by Pka1 was lost. Overexpression of Rst2 also caused sensitivity to KCl and CaCl. These findings suggest that, in addition to meiosis and glucogenesis, Rst2 is involved in cellular events such as regulation of cell growth, cell morphology, mitosis progression, microtubules structure, nuclear structure, and stress response.

Role of mitochondrial complex III/IV in the activation of transcription factor Rst2 in Schizosaccharomyces pombe

“…Rst2 was originally identified as a transcription factor to regulate meiosis and gluconeogenesis by controlling the expression of the ste11 + and fbp1 + genes (Takenaka et al., 2018; Valbuena & Moreno, 2010). It is known that Rst2 is phosphorylated and negatively regulated by PKA (Demirbas et al., 2011).…”

“…They not only regulate the specific expression of other genes, but are also regulated by upstream genes. Abnormal activation or structural and functional disorders of transcription factors cause abnormal signaling pathways, which are often associated with the development of many diseases (Asada et al., 2017; Churpek & Bresnick, 2019; Pan et al., 2018; Takenaka et al., 2018). Therefore, a better understanding of transcription factor regulatory mechanism will provide a theoretical basis for further research on signaling pathway‐related diseases and to promote the development of therapeutic strategies.…”

“…The zinc‐finger protein Rst2, as a transcription factor containing 567 amino acid residues, regulates ste11 + gene in meiosis and fbp1 + gene in glycogenesis downstream of the cyclic adenosine monophosphate (cAMP)‐dependent protein kinase (PKA) pathway (Kunitomo et al., 2000). cAMP‐PKA is widely conserved from yeasts to mammals and is also known as an important component of the glucose signaling pathway (Takenaka et al., 2018). As glucose is the main source of energy for most cells, glucose deprivation can induce various cellular processes including gene expression, metabolic change, and oxidative stress (Ferretti et al., 2012).…”

“…We have been studying the regulatory mechanism of transcription factor using the fission yeast Schizosaccharomyces pombe ( S. pombe ) as a model organism, since it shares many features with some higher eukaryotes and is amenable to genetic analysis (Hayles et al., 2013; Kato et al., 2013; Koike et al., 2012; Liu et al., 2018; Vo et al., 2016). To data, the cellular functions and regulatory mechanisms of many transcription factors have not been identified yet in S. pombe (Takenaka et al., 2018; Wood et al., 2012). Previously, we found that reactive oxygen species (ROS) and nitric oxide (NO) may be involved in glucose deprivation‐induced activation of transcription factor Rst2 (Kato et al., 2013), but whether and how other stress could induce Rst2 activation remain unknown.…”

Mal3 is a multi-copy suppressor of the sensitivity to microtubule-depolymerizing drugs and chromosome mis-segregation in a fission yeast pka1 mutant

“…Transformants carrying the mRFP-tagged sad1 gene were verified by colony PCR [29]. The mal3-13Myc- tagged strain was constructed with using the same method as that used in the construction of the mal3 -GFP strain, as previously described [30].…”