Journal of Applied Biotechnology & Bioengineering Extra Cytoplasmic Sigma Factors in Staphylococcus aureus; their Role and Significance in the Survival of Cocci Submit Manuscript | http://medcraveonline.com Abbreviations: ECF: Extra Cytoplasmic Function Factors; ELE: Enhancer-Like Elements; RNAP: RNA Polymerase; EBP: Enhancer- Binding Proteins Introduction The initiation of transcription is the most important step of gene regulation in bacteria. For the initiation of transcription, RNA polymerase has to associate with a small protein, called sigma factor (σ). This sigma factor helps to direct the RNA polymerase to bind to a specific class of Promoter sequence. Most bacterial species have ability to synthesize the different sigma- factors that recognize different promoter sequences. This is the reason why bacteria maintain basal gene expression as well as regulation of gene expression in response to altered environmental stimuli or developmental signals [1]. Apart from these σ factors bacteria encode thousands of different cell proteins necessary for the regular cellular activities and adaption to changed environmental conditions. The requirement of these protein is different as it changes with time and place in cell. Regulation of gene expression enables the cell to control the production of protein required to a cell at appropriate time of the cell cycle or for the adaption in the extracellular environmental changes. This regulation in turn makes it possible for the bacterium to adequately adapt to rapid changes in the environment. The regulation is either at transcription or at translation process. A key enzyme DNA- dependent RNA polymerase (RNAP) initiates the process of transcription which is the most prominent step in the gene regulation. The DNA-dependent RNA polymerase (RANP) catalyzes the synthesis of RNA from a DNA template. However, RANP is not able to initiate the process of transcription by itself. In addition, it requires a polypeptide known as σ factor. It is a family of relatively small molecular weight proteins most of the time associated with RANP in reversible manner. Collectively it forms an initiation specific enzyme, referred as holoenzyme [1]. This variety in σ factors provides the opportunity to the bacterium to maintain basal gene expression as well as for regulation of gene expression in response to altered environmental conditions [2]. Bacterial initiation of transcription in is a multistep process which begins with the binding of RNAP holoenzyme, containing σ70 or a σ70-related σ-factor, to a specific DNA sequence recognized as a promoter. Recognition of a promoter sequence is directed primarily by the σ- subunit of the RNAP holoenzyme. Volume 1 Issue 2 - 2016 Department of Biosciences and Technology, Defence Institute of Advanced Technology, India *Corresponding author: Gajanan K Arbade, Department of Biosciences and Technology, Defence Institute of Advanced Technology, Girinagar, Pune-411025, MS, India, Email: Received: October 25, 2016 | Published: December 07, 2016 Mini Review J Appl Biotechnol Bioeng 2016, 1(2): 00009 Abstract Bacterial sigma (σ) factors are an essential component of RNA polymerase. It determines the promoter selectivity. Alternative σ factors play key roles in the coordinating gene transcription during various environmental stresses, nutrient starvation responses and during morphological development. The extra cytoplasmic function (ECF) σ factors are small re BOH 3 gulatory proteins that are quite divergent in sequence relative to most other σ factors. In many bacteria with complex genome, contain multiple ECF σ factors and these regulators often outnumber all other types of σ factor combined. The roles and mechanisms of regulation for these various ECF σ factors are largely unknown, but significant progress has been made in selected systems like Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Mycobacterium tuberculosis. Most ECF σ factors are co-transcribed with one or more negative regulators. Upon receiving an appropriate environmental stimulus, the σ factor is released and can bind to RNA polymerase to stimulate transcription. S. aureus causes a variety of human and animal infections. It produces multiple virulence factors as well as different regulators for controlling the expression of virulence factors. Prevention of staphylococcal infections is becoming problematic primarily because of the emergence and dissemination of the multiple-drug-resistant S. aureus strains across the world. Novel anti-staphylococcal drugs are required to eradicate all the S. aureus strains. The depth study of structural characterization of the primary and alternative sigma factors of S. aureus may provide a novel way for the development of anti-staphylococcal drug, as most of them are involved in the regulation of gene expression. The present review studies involve the important aspects ECF σ factors in pathogenesis. Keywords: Extra cytoplasmic function (ECF); σ factors; S. aureus; Stress response; Transcription regulation