The heat shock response mediated by transcription factor σ32 is a major stress response to cope with heat and other stresses in Escherichia coli. Although much attention has been paid to the role of highly conserved heat shock proteins such as chaperones and proteases in sustaining cellular protein homeostasis under stress, relatively little is known about the dynamic nature of underlying regulatory mechanisms. When cells are suddenly exposed to high temperature, synthesis of σ32 is rapidly induced by activated translation of rpoH mRNA, which encodes σ32, through disruption of mRNA secondary structure. The increased synthesis of σ32 is accompanied by stabilization of σ32, which is normally very unstable and rapidly degraded by the membrane-localized FtsH protease. It was recently found that σ32 must be localized to the inner membrane by the SRP-dependent pathway to work properly for regulation, but the roles played by membrane and other components of the cell remained unknown. Random transposon mutagenesis of the strongly deregulated I54N-σ32 mutant has now started to unravel the complex regulatory circuit, involving membrane protein(s), other cellular components or σ32-interfering polypeptides, for dynamic fine-tuning of σ32 activity that could be of vital importance for cell survival.
Interleukins play important roles in pregnancy. Altered expression and splicing of various interleukins have been linked to the pathophysiology of recurrent pregnancy loss. Polymorphisms in interleukin genes can affect the expression and/or splicing of their respective genes and thus influence the risk of recurrent pregnancy loss. In this work, we examined the association between the IL1B rs16944, IL1B rs1143634, IL6 rs1800795, IL6 rs1800796, IL10 rs1800896 and IL18 rs187238 polymorphisms and recurrent pregnancy loss risk in a Chinese population. Study subjects comprised 598 idiopathic recurrent pregnancy loss patients and 603 controls. The genotyping was accomplished by PCR-RFLP. Regression analysis was performed to evaluate the disease association. After adjustment by Bonferroni correction, only the IL1B rs16944 and IL6 rs1800796 polymorphisms were significantly associated with risk of recurrent pregnancy loss. The heterozygous TC genotype of IL1B rs16944 had an adjusted odds ratio (aOR) of 1.4209 (1.1302–1.8929) (P = 0.0019), while the homozygous CC genotype had an aOR of 1.7398 (1.2133–2.3203) (P = 0.0008). A significant association was also observed for the C allele [aOR = 1.3747 (1.1296–1.8972)] (P = 0.0003). For IL6 rs1800796, the heterozygous CG genotype, the homozygous GG genotype and the G allele had aORs of 0.7342 (0.4412–0.8423) (P = 0.0016), 0.5424 (0.1768–0.7865) (P = 0.0014) and 0.7009 (0.4511–0.8034) (P = 0.0007), respectively. In summary, the IL1B rs16944 and IL6 rs1800796 variants were associated with an increased and a decreased recurrent pregnancy loss risk, respectively.
The role of cyclin-dependent kinase inhibitor 2A gene (CDKN2A) variants in breast cancer is not well understood, here we investigated their possible effects on breast cancer in Pakistani women attending the NORI Hospital, Islamabad. Direct DNA sequencing of CDKN2A identified an already known polymorphism in the 3′ UTR, c.*29G>C (rs11515), in 5.88% patients and two novel variants. One, a deep intronic substitution (c.458-554T>G) in 1.96% patients, is also detected as a compound heterozygous form along with c.*29G>C in 1.96% patients (c.[458-554T>G; *29G>C]). The other is a novel deletion (c.458-82delG) occurring as a compound variant with two other identified variants c.[458-554T>G; 458-82delG; *29G>C] in 1.96% patients. In silico pathogenicity prediction analyses did not predict pathogenic effects on breast cancer for these individual variants. We conclude that variations in CDKN2A are not the major genetic cause of breast cancer in the enrolled Pakistani patients.
Cellular aging is characterized by the loss of DNA replication capability and is mainly brought about by various changes in chromatin structure. Here, we examined changes in MCM2–7 proteins, which act as a replicative DNA helicase, during aging of human WI38 fibroblasts at the single-cell level. We used nuclear accumulation of p21 as a marker of senescent cells, and examined changes in MCM2–7 by western blot analysis. First, we found that senescent cells are enriched for cells with a DNA content higher than 4N. Second, the levels of MCM2, MCM3, MCM4 and MCM6 proteins decreased in senescent cells. Third, cytoplasmic localization of MCM2 and MCM7 was observed in senescent cells, from an analysis of MCM2–7 except for MCM5. Consistent with this finding, fragmented MCM2 was predominant in these cells. These age-dependent changes in MCM2–7, a protein complex that directly affects cellular DNA replication, may play a critical role in cellular senescence.
Commelina communis f. ciliata (Commelinaceae), a newly distinguished taxon, is an annual andromonoecious herb exhibiting a mixed mating system, the details of which remain unclear. We developed microsatellite markers for use in exploring the evolution of andromonoecy and mixed mating in the species. Fifteen microsatellite loci were developed using next-generation sequencing. The primer sets were used to evaluate 65 C. communis f. ciliata individuals from three populations in Japan; we found 1–13 alleles per locus and the expected heterozygosity ranged from 0.00 to 0.76. The markers are potentially useful to examine intra- and interspecies genetic structure and the mixed mating strategy of Commelina species via paternity analysis.
On page 126, on the bottom line of the left column, the sentence opening “Conversion of these two conserved basic amino acids in either Mcm4, 6 or 7 in S. cerevisiae to aspartic acid did not affect cell growth,” should be changed to “Conversion of these two conserved basic amino acids in either Mcm4, 6 or 7 in S. cerevisiae to alanine did not affect cell growth,”.
On page 127, in the Fig. 3 legend, the second sentence “Two conserved basic amino acids in the amino-terminal region of Mcm4, 6 and 7 proteins were mutated to aspartic acid in S. cerevisiae (Froelich et al., 2014).” should be changed to “Two conserved basic amino acids in the amino-terminal region of Mcm4, 6 and 7 proteins were mutated to alanine in S. cerevisiae (Froelich et al., 2014); the suffix D indicates double-alanine mutation”.