Endoribonuclease ENDU-2 regulates multiple traits including cold tolerance via cell autonomous and nonautonomous controls in .

Environmental temperature acclimation is essential to animal survival, yet thermoregulation mechanisms remain poorly understood. We demonstrate cold tolerance in as regulated by paired ADL chemosensory neurons via Ca-dependent endoribonuclease (EndoU) ENDU-2. Loss of ENDU-2 function results in life span, brood size, and synaptic remodeling abnormalities in addition to enhanced cold tolerance.

Epistasis analysis between homologous recombination genes in Saccharomyces cerevisiae identifies multiple repair pathways for Sgs1, Mus81-Mms4 and RNase H2.

The DNA repair genes SGS1 and MUS81 of Saccharomyces cerevisiae are thought to control alternative pathways for the repair of toxic recombination intermediates based on the fact that sgs1Δ mus81Δ synthetic lethality is suppressed in the absence of homologous recombination (HR). Although these genes appear to functionally overlap in yeast and other model systems, the specific pathways controlled by SGS1 and MUS81 are poorly defined. Epistasis analyses based on DNA damage sensitivity previously indicated that SGS1 functioned primarily downstream of RAD51, and that MUS81 was independent of RAD51.

Rif1 provides a new DNA-binding interface for the Bloom syndrome complex to maintain normal replication.

BLM, the helicase defective in Bloom syndrome, is part of a multiprotein complex that protects genome stability. Here, we show that Rif1 is a novel component of the BLM complex and works with BLM to promote recovery of stalled replication forks. First, Rif1 physically interacts with the BLM complex through a conserved C-terminal domain, and the stability of Rif1 depends on the presence of the BLM complex.

Yeast 18 S rRNA is directly involved in the ribosomal response to stringent AUG selection during translation initiation.

In eukaryotes, the 40 S ribosomal subunit serves as the platform of initiation factor assembly, to place itself precisely on the AUG start codon. Structural arrangement of the 18 S rRNA determines the overall shape of the 40 S subunit. Here, we present genetic evaluation of yeast 18 S rRNA function using 10 point mutations altering the polysome profile.

The eukaryotic initiation factor (eIF) 4G HEAT domain promotes translation re-initiation in yeast both dependent on and independent of eIF4A mRNA helicase.

Translation re-initiation provides the molecular basis for translational control of mammalian ATF4 and yeast GCN4 mediated by short upstream open reading (uORFs) in response to eIF2 phosphorylation. eIF4G is the major adaptor subunit of eIF4F that binds the cap-binding subunit eIF4E and the mRNA helicase eIF4A and is also required for re-initiation in mammals. Here we show that the yeast eIF4G2 mutations altering eIF4E- and eIF4A-binding sites increase re-initiation at GCN4 and impair recognition of the start codons of uORF1 or uORF4 located after uORF1.

Eukaryotic initiation factor (eIF) 1 carries two distinct eIF5-binding faces important for multifactor assembly and AUG selection.

Eukaryotic initiation factor (eIF) 1 is a small protein (12 kDa) governing fidelity in translation initiation. It is recruited to the 40 S subunit in a multifactor complex with Met-tRNA(i)(Met), eIF2, eIF3, and eIF5 and binds near the P-site. eIF1 release in response to start codon recognition is an important signal to produce an 80 S initiation complex.

Mus81 functions in the quality control of replication forks at the rDNA and is involved in the maintenance of rDNA repeat number in Saccharomyces cerevisiae.

Previous studies in yeast have suggested that the SGS1 DNA helicase or the Mus81-Mms4 structure-specific endonuclease is required to suppress the accumulation of lethal recombination intermediates during DNA replication. However, the structure of these intermediates and their mechanism of the suppression are unknown. To examine this reaction, we have isolated and characterized a temperature-sensitive (ts) allele of MUS81.

Slx4 regulates DNA damage checkpoint-dependent phosphorylation of the BRCT domain protein Rtt107/Esc4.

RTT107 (ESC4, YHR154W) encodes a BRCA1 C-terminal-domain protein that is important for recovery from DNA damage during S phase. Rtt107 is a substrate of the checkpoint protein kinase Mec1, although the mechanism by which Rtt107 is targeted by Mec1 after checkpoint activation is currently unclear. Slx4, a component of the Slx1-Slx4 structure-specific nuclease, formed a complex with Rtt107.

Roles of SGS1, MUS81, and RAD51 in the repair of lagging-strand replication defects in Saccharomyces cerevisiae.

Yeast cells lacking the SGS1 DNA helicase and the MUS81 structure-specific endonuclease display a synthetic lethality that is suppressed by loss of the RAD51 recombinase. This epistatic interaction suggests that the primary function of SGS1 or MUS81, or both genes, is downstream of RAD51. To identify RAD51-independent functions of SGS1 and MUS81, a synthetic-lethal screen was performed on the sgs1 mus81 rad51triple mutant.

Efficient incorporation of eukaryotic initiation factor 1 into the multifactor complex is critical for formation of functional ribosomal preinitiation complexes in vivo.

Eukaryotic initiation factor 1 (eIF1) is a low molecular weight factor critical for stringent AUG selection in eukaryotic translation. It is recruited to the 43 S complex in the multifactor complex (MFC) with eIF2, eIF3, and eIF5 via multiple interactions with the MFC constituents. Here we show that FLAG epitope tagging of eIF1 at either terminus abolishes its in vitro interactions with eIF5 and eIF2beta but not that with eIF3c.

The yeast eukaryotic initiation factor 4G (eIF4G) HEAT domain interacts with eIF1 and eIF5 and is involved in stringent AUG selection.

Eukaryotic initiation factor 4G (eIF4G) promotes mRNA recruitment to the ribosome by binding to the mRNA cap- and poly(A) tail-binding proteins eIF4E and Pap1p. eIF4G also binds eIF4A at a distinct HEAT domain composed of five stacks of antiparallel alpha-helices. The role of eIF4G in the later steps of initiation, such as scanning and AUG recognition, has not been defined.