Journal of Cell and Molecular Research

1-10

Authors: Mahnaz Aghdasi, Fariba Fazli and Mohammad Bagher Bagherieh

TRR14 is a novel protein important in trehalose (α-D-glucosyl-[1,1]-α-D-glucopyranoside) signaling in Arabidopsis. In this research, we provided evidences to demonstrate that TRR14 plays role in Arabidopsis responses to salt and drought stress. Transgenic Arabidopsis plants over-expressing TRR14 under the control of CaMV 35S promoter were generated. The transformed lines showed higher transcript levels of TRR14 than that of the Wild Type (WT) Arabidopsis plants. The RT-PCR results showed that TRR14 transcript level increased markedly by salt and drought stress both in WT and transformed lines. Further experiments indicated that the TRR14 transformed lines had unchanged seed germination, root length and chlorophyll content under stress conditions. In addition, the activity of oxidative enzymes like peroxidase and catalase were significantly induced in transformed lines under salt and drought treatments. Thus, the present data indicate that a novel protein, TRR14, is involved in plant salt and drought tolerance.

18-27

Authors: Hassan Monhemi, Mohammad Reza Housaindokht, Mohammad Reza Bozorgmehr and Ahmad Reza Bahrami

Signaling pathways are not isolated from their surroundings. They are also intervened by other signaling pathways known as “crosstalk mechanism”. One of the most important crosstalk mechanisms is the insulin- EGF network. Although insulin and epidermal growth factor (EGF) networks have some complexity in their isolated forms, their complexities will grow in the crosstalk network. In this study, we used the analytical tools of the systems biology workbench for elucidating some ambiguities of the insulin-EGF crosstalk. Based on sensitivity analysis, we reconstructed an elucidated model with 51 chemical reactions in comparison with the previous model with 111 chemical reactions. Interestingly, this reduced model reproduces the results of the original model in synergy conditions. We noticed two controlling pathways with direct participation of phosphorylated insulin and EGF receptors that involve Insulin Receptor Substrate (IRS) and Src kinase modules. Also, insulin pathway by producing phosphatidylinositol-3, 4, 5-triphosphate (PIP3), and EGF pathway by activation of GAB1, control the downstream events and lead to potentialities in the mitogenic signal. Surprisingly, Shc and phosphatase SHP2-dependent reactions have no significant roles in the synergy conditions and are not involved in the reduced model. Regarding sensitivity analysis, all Ras/ERK cascade reactions are crucial for signal transduction and were kept in the reduced model.

34-42

Authors: Somayeh Panahi Moghadam, Zohreh Hojati and Majid Motovali-Bashi

StrR is a putative pathway specific regulator of streptomycin production in Streptomyces griseus. Because of finding new spo0j domain in strR by bioinformatics methods, the purpose of this study was to suggest another role for strR gene. This domain can be seen in proteins that are involved in initiation of sporulation and normal chromosome partitioning. So, 51 bps of strR in accordance to spo0j domain was deleted to investigate effects of deletion mutation in StrR functions. A unique specific procedure, including three consecutive PCRs, known as SOEing PCR were used here for site directed mutagenesis. Application and feasibility of this PCR was studied here. Bioinformatic studies were carried out for comparison of the sequence similarities between StrR and Spo0J proteins. An exclusive procedure, including three consecutive PCRs, was designed here in order to delete a 51 bp from the native strR. Other PCRs such as Semi-Nested PCR and RFLP PCR were used for strR isolation and structural confirmation of the isolated strR and deleted strR genes. Routine genetic engineering procedures were conducted in order to clone the native and deleted strR genes into E. coli. Obtained sequence information, from Conserved Domains Database (CDD) and Clustal W program, revealed that the StrR is similar to members of ParB family. Here, the strR was initially isolated from Iranian strain of Streptomyces griseus (PTCC1127). It was then confirmed as StrR by Semi-Nested PCR and RFLP-PCR. A 51 base pair region of the strR gene was deleted by specifically designed overlapped primers. A ten nucleotide overlap region was considered for a set of these primers. The recombinant cassette pSPMstrRΔ17 was constructed and cloned in E. coli. The sequencing results showed that a specific deletion is produced in the desired site and region in the strR gene. Therefore the designed three steps PCRs (known as SOing PCR) is a very rapid, cheap, and precise method for introducing such a deletion in any preferred gene.