These last two proteins are the only two elements of the replisome that are not encoded in the M. endobia genome. However, mutations in dnaC which have the ability to bypass such requirements Selleckchem SB525334 in the loading of DnaB have been described [32], and dnaC is also absent in other reduced genomes that have been characterized (e.g. Blochmannia floridanus[21], Wigglesworthia

glossinidia[22] or Mycoplasma genitalium[33]). Additionally, the role of DnaT in primosome assembly has not been fully elucidated [34]. Therefore, it cannot be ruled out that dnaT is not essential for the functioning of the homologous recombination system in this bacterial consortium. RNA Metabolism Even though most genes present in the T. princeps genome are involved in RNA metabolism (78 out of 116 genes, occupying 35% of its genome length and 49% of its coding capacity) [16, 19], it still seems to depend on M. endobia for transcription and translation. Thus, T. princeps encodes every essential subunit of the core RNA polymerase (rpoBCA) and a single sigma factor (rpoD), but no other genes selleck kinase inhibitor involved in the basic transcription machinery or in RNA processing and degradation are present in its genome. On the other hand, M. endobia possesses a minimal but yet complete transcription

machinery [35] plus some additional genes, including the ones encoding the ω subunit of the RNA polymerase (rpoZ), the sigma-32 factor (rpoH), and the transcription factor Rho. It also presents several genes involved in the processing and degradation of functional RNAs, i.e.

pnp, rnc (processing of rRNA and CP-868596 solubility dmso regulatory antisense RNAs), hfq (RNA chaperone), rne, orn, rnr (rRNA maturation and mRNA regulation in stationary phase), and rppH (mRNA degradation). It is surprising that the small genome of M. endobia has also retained several transcriptional regulators, the functions of which are not yet fully understood, and which are absent in other endosymbionts with reduced genomes. These include CspB and CspC (predicted DNA-binding transcriptional regulators under stress conditions), and NusB, which is required in E. coli for proper transcription Megestrol Acetate of rRNA genes, avoiding premature termination [36]. cpxR, encoding the cytoplasmic response regulator of the two-component signal transduction system Cpx, the stress response system that mediates adaptation to envelope protein misfolding [37], is also preserved, while the companion sensor kinase cpxA appears to be a pseudogene. This might be an indication of a constitutive activation of the regulatory protein. Regarding translation, an extremely complex case of putative complementation between both bacteria is predicted, which would represent the first case ever described for this function. Thus, only M.