Biology subjects

Bairwa, N. K.

Publications and source records attributed to Bairwa, N. K..

3 recordsLinked to original sources

bioRxiv2019

Absence of Replication fork associated factor CTF4 and F-box motif Encoding Gene SAF1 leads to reduction in Cell Size and Stress Tolerance Phenotype in S. cerevisiae

Chromosome transmission fidelity factor, Ctf4 in S. cerevisiae associates with replication fork and helps in the sister chromatid cohesion. At the replication fork, Ctf4 links DNA helicase with the DNA polymerase. The absence of Ctf4 invokes replication checkpoint in the cells. The Saf1 of S.cerevisiae interacts with Skp1 of SCF-E3 ligase though F box-motif and ubiquitinates the adenine deaminase Aah1 during phase transition due to nutrient stress. The genetic interaction between the CTF4 and SAF1 has not been studied. Here we report genetic interaction between CTF4 and SAF1 which impacts the growth fitness and response to stress. The single and double gene deletions of SAF1 and CTF4 were constructed in the BY4741 genetic background. The strains were tested for growth on rich media and media containing stress causing agents. The saf1{Delta}ctf4{Delta} cells with reduced cell size showed the fastest growth phenotype on YPD medium when compared with the saf1{Delta}, ctf4{Delta}, and WT. The saf1{Delta}ctf4{Delta} cells also showed the tolerance to MMS, NaCl, Glycerol, SDS, Calcofluor white, H2O2, DMSO, Benomyl, and Nocodazole when compared with the saf1{Delta}, ctf4{Delta}, and WT cells. However, saf1{Delta}ctf4{Delta} cells showed the sensitivity to HU when compared with WT and saf1{Delta}. Based on these observations we suggest that SAF1 and CTF4 interact genetically to regulate the cell size, growth and stress response.

genetics↗

bioRxiv2019

The absence of F-box motif Encoding Gene SAF1 and Chromatin Associated factor CTF8 together contributes to MMS Resistant and HU Sensitive phenotype in S. cerevisiae

The Replication factor-C compex which related to cohesion, constitutes, three subunits called Ctf18, Ctf8 and Dcc1. These three subunit complex assist the loading of PCNA onto the chromosome. None of the replication factor C components are essential for cell viability. The null mutant of the CTF8 in S.cerevisiae shows the chromosome instability and high frequency of chromosome loss. The SAF1 gene product of S. cerevisiae involved in the degradation of adenine deaminase factor Aah1p by SCF-E3 ligase, which itself is the part of E3 ligase. The ubiquitin marked degradation of Aah1p occurs during nutrient stress which lead to cell enter into the quiescent state. The N-terminus of Saf1p interacts with the Skp1 of SCF-E3 ligase and at C-terminus recruits with Aah1p. Here we have investigated about the binary genetic interaction between the SAF1 and CTF8 genes. The strains containing single and double gene deletions of SAF1 and CTF8 were constructed in the BY4741 genetic background. Further the mutant strains were evaluated for growth fitness, genome stability and response to genotoxic stress caused by hydroxyurea (HU) and methyl methane sulfonate (MMS). The saf1{Delta}ctf8{Delta} strain showed the increased growth phenotype in comparison to saf1{Delta}, ctf8{Delta}, and WT strain on YPD medium. However saf1{Delta}ctf8{Delta} strain when grown in the presence MMS showed resistance and HU sensitive phenotype when compared with saf1{Delta}, ctf8{Delta}. The frequency of Ty1 retro-transposition was also elevated in saf1{Delta}ctf8{Delta} in comparison to either saf1{Delta} or ctf8{Delta}. The number of cells showing the two or multi-nuclei phenotype was also increased in saf1{Delta}ctf8{Delta} cells when compared with the either saf1{Delta} or ctf8{Delta}. Based on these observations, we report that the absence of both the gene SAF1 and CTF8 together leads to MMS resistance, HU sensitivity, and genome instability. This report warrants the investigation of mechanisms of differential growth phenotype due to loss of SAF1 and CTF8 together in presence of genotoxic stress in future.

genetics↗

bioRxiv2019

Loss of F-box Motif Encoding Gene SAF1 and RRM3 Together Leads to Synthetic Growth Defect and Sensitivity to HU, MMS in S.cerevisiae

Unearthing of novel genetic interaction which leads to synthetic growth defects due to inactivation of genes are needed for applications in precision medicine. The genetic interactions among the molecular players involving different biological pathways need to be investigated. The SAF1 gene of S.cerevisiae encodes for a protein product which contain N-terminal F-box motif and C-terminal RCC1 domain. The F-box motif interacts with Skp1subunit of the SCF-E3 ligase and C-terminus with Aah1 (adenine deaminase) for ubiquitination and subsequent degradation by 26S proteasome during phase transition from proliferation state to quiescence phase due to nutrient limitation stress. The replication fork associated protein Rrm3 of S.cerevisiae belongs to Pif1 family helicase and function in removal of the non-histone proteins during replication fork movement. Here we have investigated the genetic interaction among both the genes (SAF1 and RRM3) and their role in growth fitness and genome stability. The single and double gene knockout strains of SAF1and RRM3 genes was constructed in BY4741 genetic background and checked for the growth fitness in presence of genotoxic stress causing agents such as hydroxyurea and methyl methanesulfonate. The strains were also evaluated for nuclear migration defect by DAPI staining and for HIS3AI marked Ty1 retro-transposition. The saf1{Delta}rrm3{Delta} showed the extremely slow growth phenotype in rich medium and sensitivity to genotoxic agents such as HU and MMS in comparison to single gene mutant (saf1{Delta}, rrm3{Delta}) and WT cells. The saf1{Delta}rrm3{Delta} also showed the defects in nuclear migration as evident by multi-nuclei phenotype. The saf1{Delta}rrm3{Delta} also showed the elevated frequency of Ty1 retro-transposition in JC2326 background in comparison to either saf1{Delta} or rrm3{Delta}. Based on these observations we report that thatSAF1 and RRM3 functions in parallel pathway for growth fitness and stability of the genome.

genetics↗