IsiA is a membrane-bound Chl a-antenna protein synthesized in cyanobacteria under iron deficiency. Since iron deficiency is a common nutrient stress in significant fractions of cyanobacterial habitats, IsiA is likely to be essential for some cyanobacteria. However, the role it plays in cyanobacteria is not fully understood. In this review paper, we summarize the research efforts directed towards characterizing IsiA over the past three decades and attempt to bring all the pieces of the puzzle together to get a more comprehensive understanding of the function of this protein. Moreover, we analyzed the genomes of over 390 cyanobacterial strains available in the JGI/IMG database to assess the distribution of IsiA across the cyanobacterial kingdom. Our study revealed that only 125 such strains have an IsiA homolog, suggesting that the presence of this protein is a niche specific requirement, and cyanobacterial strains that lack IsiA might have developed other mechanisms to survive iron deficiency., H.-Y. S. Chen, A. Bandyopadhyay, H. B. Pakrasi., and Obsahuje bibliografické odkazy
The ribosomal protein S6 kinase (S6K) plays a pivotal role in developmental processes and cell survival by participating in protein synthesis relevant signaling pathways. In the present study, an S6K gene (AccS6K-p70) was isolated and characterized from the Chinese honeybee, Apis cerana cerana (Fabricius) (Hymenoptera: Apidae), an important economic insect in the agricultural industry. The cDNA of AccS6K-p70 was 1683 bp in length and predicted to encode a protein of 467 amino acid residues. Sequence and structure analysis showed that there was a conserved catalytic domain in AccS6K-p70, whilst a phosphorylation site was found in the conserved part of the catalytic domain. Development relevant transcription factor binding sites found in the 5’-flanking region of AccS6K-p70 suggest that AccS6K-p70 might be involved in A. c. cerana development. Furthermore, quantitative PCR revealed that the expression levels of AccS6K-p70 were higher in head and thorax than in other tissues. The AccS6K-p70 was highly expressed in both larvae and adults compared with that in pupae, whilst expression of the gene was significantly down-regulated by hydrogen peroxide (H2O2) (although initially and slightly increased by it) and pyriproxyfen (a juvenile hormone analogue insecticide) stresses. These results suggest that AccS6K-p70 may play critical roles in developmental processes and cell survival in A. c. cerana, whilst both oxidative stress and pyriproxyfen may impair S6K-p70 mediated developmental processes by down-regulation of AccS6K-p70 expression., Yingqi Cai ... [et al.]., and Obsahuje seznam literatury