Characterization of a fission yeast gene, gpa2, that encodes a G alpha subunit involved in the monitoring of nutrition.

Isshiki, Takako; Mochizuki, Naoki; Maeda, Tatsuya; Yamamoto, Masayuki

doi:10.1101/gad.6.12b.2455

Cited by 155 publications

(157 citation statements)

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“…Sporulation agar medium containing 10 g͞liter of glucose, 1 g͞liter of KH 2 PO 4 , 1 ml of ϫ1,000 vitamin stock solution per liter Ϫ1 , or malt extract agar medium was used for genetic crosses and sporulation. Nitrogen-free derivative MM-N was used for nitrogen starvation experiments as de- scribed (40). General genetic methods (41) and the procedure for transformation (42) were as described.…”

Section: Methodsmentioning

confidence: 99%

Hsk1 kinase is required for induction of meiotic dsDNA breaks without involving checkpoint kinases in fission yeast

Ogino¹,

Hirota

Matsumoto³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Cdc7 kinase, conserved through evolution, is known to be essential for mitotic DNA replication. The role of Cdc7 in meiotic recombination was suggested in Saccharomyces cerevisiae, but its precise role has not been addressed. Here, we report that Hsk1, the Cdc7-related kinase in Schizosaccharomyces pombe, plays a crucial role during meiosis. In a hsk1 temperature-sensitive strain (hsk1-89), meiosis is arrested with one nucleus state before meiosis I in most of the cells and meiotic recombination frequency is reduced by one order of magnitude, whereas premeiotic DNA replication is delayed but is apparently completed. Strikingly, formation of meiotic dsDNA breaks (DSBs) are largely impaired in the mutant, and Hsk1 kinase activity is essential for these processes. Deletion of all three checkpoint kinases, namely Cds1, Chk1, and Mek1, does not restore DSB formation, meiosis, or Cdc2 activation, which is suppressed in hsk1-89, suggesting that these aberrations are not caused by known checkpoint pathways but that Hsk1 may regulate DSB formation and meiosis. Whereas transcriptional induction of some rec genes and horsetail movement are normal, chromatin remodeling at ade6-M26, a recombination hotspot, which is prerequisite for subsequent DSB formation at this locus, is not observed in hsk1-89. These results indicate unique and essential roles of Hsk1 kinase in the initiation of meiotic recombination and meiosis.Cdc7-related kinase ͉ checkpoint control ͉ chromatin remodeling ͉ meiosis ͉ meiotic recombination A lthough recent studies revealed the presence of a number of conserved factors involved in mitotic DNA replication (1), it is largely unknown whether they play roles in meiotic replication and recombination (2, 3). Studies in fission and budding yeasts indicated essential roles of Cdc2 kinase (1) and Clb5-and Clb6-dependent Cdc28 kinase (4), respectively, in premeiotic DNA replication. Orc, Cdc18, and MCM are also required for premeiotic DNA synthesis (3, 5), although their requirement may not be identical to that during mitotic replication (2). It is not known whether initiation is regulated by a common mechanism or the same set of replication origins is used during premeiotic S phase. In budding yeast, strong coupling of DNA replication and meiotic recombination has been shown (6-9).Cdc7 kinase plays an essential role in firing replication origins during mitotic growth (10, 11). It was reported previously that meiotic recombination frequency is reduced, whereas premeiotic DNA replication proceeds, in the budding yeast cdc7 ts mutants and that Cdc7 may play a role in synaptonemal complex formation during meiosis, a step stabilizing homologous pairing during meiotic recombination (12,13), but the precise meiotic roles of Cdc7 have remained elusive. We report here that Hsk1, the fission yeast homologue of Cdc7 kinase, is required for efficient meiotic recombination and meiotic nuclear division. During meiosis, Hsk1 is required specifically for formation of dsDNA breaks (DSBs), an early event for meiotic recombinatio...

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Section: Methodsmentioning

confidence: 99%

Hsk1 kinase is required for induction of meiotic dsDNA breaks without involving checkpoint kinases in fission yeast

Ogino¹,

Hirota

Matsumoto³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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“…In budding yeast, glucose depletion also induces autophagy (Takeshige et al, 1992). Environmental glucose is monitored by a cAMP-PKA cascade in both budding and fission yeast (Isshiki et al, 1992;Maeda et al, 1990Maeda et al, , 1994Welton & Hoffman, 2000). reported that addition of a high concentration of cAMP repressed autophagy in budding yeast.…”

Section: Processing Of Gfp-atg8 Under Various Autophagy-inducing Condmentioning

confidence: 99%

Autophagy-deficient Schizosaccharomyces pombe mutants undergo partial sporulation during nitrogen starvation

et al. 2009

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Autophagy is triggered when organisms sense radical environmental changes, including nutritional starvation. During autophagy, cytoplasmic components, including organelles, are enclosed within autophagosomes and are degraded upon lysosome-vacuole fusion. In this study, we show that processing of GFP-tagged Atg8 can serve as a marker for autophagy in the fission yeast Schizosaccharomyces pombe. Using this marker, 13 Atg homologues were also found to be required for autophagy in fission yeast. In budding yeast, autophagy-deficient mutants are known to be sterile, whereas in fission yeast we found that up to 30 % of autophagy-defective cells with amino acid auxotrophy were able to recover sporulation when an excess of required amino acids was supplied. Furthermore, we found that approximately 15 % of the autophagydefective cells were also able to sporulate when a prototrophic strain was subjected to nitrogen starvation, which suggested that fission yeast may store sufficient intracellular nitrogen to allow partial sporulation under nitrogen-limiting conditions, although the majority of the nitrogen source is supplied by autophagy. Monitoring of the sporulation process revealed that the process was blocked non-specifically at various stages in the atg1D and atg12D mutants, possibly due to a shortage of amino acids. Taking advantage of this partial sporulation ability of fission yeast, we sought evidence for the existence of a recycling system for nitrogen sources during starvation. INTRODUCTIONAutophagy is a degradative pathway conserved among eukaryotic cells, and is responsible for turnover of damaged organelles and long-lived proteins. When living organisms are exposed to radical environmental changes such as nutrient starvation, differentiation or development, autophagy is rapidly induced and inner cell components are reorganized. In the budding yeast Saccharomyces cerevisiae, autophagy is triggered by starvation for nitrogen or carbon, after which endogenous proteins and organelles are enclosed within isolated membranes called autophagosomes. The outer membrane of the autophagosome then fuses with the vacuole, allowing the contents of the autophagosome, designated autophagic bodies, to be released and degraded in the vacuole. The molecular mechanisms involved in the process of autophagy have been subjected to detailed genetic analysis and more than 20 AuTophaGy-related (ATG) genes essential for autophagy have been identified in Sac. cerevisiae Kamada et al., 2000;Mizushima et al., 1998).One of the most striking findings with respect to function of the Atg proteins was the discovery of two ubiquitin-like conjugation systems involving Atg12p and Atg8p (Ohsumi, 2001). Atg12p, which has no apparent homology to ubiquitin, covalently attaches to Atg5p in a manner analogous to ubiquitination, and then forms a complex with Atg16p. Atg8p also lacks similarity to ubiquitin, but Abbreviations: DAPI, 49,6-diamidino-2-phenylindole; DIC, differential interference contrast; FSM, forespore membrane.Two supplementary tables a...

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“…One potential explanaion for this observation is that the cell surface NK2 receptor s able to interact with an endogenous S. pombr heterotrimeric ;-protein resulting in stabilization of a high-affinity agonist eceptor-binding state [42]. Currently, two endogenous G-proein a-chains, termed gpal and gpa2, have been identified mol-,cularly in fission yeast [20,21] and both represent candidate ,omponents for such an interaction. However, while this is not ,xcluded, receptor theory [42] predicts that normal levels of :uanine nucleotide within yeast cytosol should disrupt recepor-G-protein ternary complex and with it abolish high-affinity agonist binding in intact cells.…”

Section: Immunodetection Qfmentioning

confidence: 99%

Co‐expression of the neurokinin NK2 receptor and G‐protein components in the fission yeast Schizosaccharomyces pombe

Arkinstall¹,

Edgerton²,

Payton³

et al. 1995

FEBS Letters

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ibstract The fission yeast Schizosaccharomyces pombe has proven useful for studying molecular interactions between a range *)f signal transduction components. We now report the first coexpression of a mammalian seven-transmembrane receptor and G-protein components in S. pombe. We selected the human neurokinin NK2 receptor together with its G-protein-signalling partoer G, for this study. Yeast membrane fractions showed high levels of NK2 receptor-binding activity (

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Characterization of a fission yeast gene, gpa2, that encodes a G alpha subunit involved in the monitoring of nutrition.

Cited by 155 publications

References 31 publications

Hsk1 kinase is required for induction of meiotic dsDNA breaks without involving checkpoint kinases in fission yeast

Hsk1 kinase is required for induction of meiotic dsDNA breaks without involving checkpoint kinases in fission yeast

Autophagy-deficient Schizosaccharomyces pombe mutants undergo partial sporulation during nitrogen starvation

Co‐expression of the neurokinin NK2 receptor and G‐protein components in the fission yeast Schizosaccharomyces pombe

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