Complete genome sequence of the Microbacterium foliorum bacteriophage Garey24

In this work, we report the discovery and characterization of Garey24, a bacteriophage that forms medium-size plaques with halo rings isolated from a soil sample in Funes, Argentina. Its 41,522 bp circularly permuted genome contains 63 putative protein-coding genes. Based on gene content similarity, Garey24 was assigned to subcluster EA1.

The multifarious MerR family of transcriptional regulators

The MerR family of transcriptional regulators includes a variety of bacterial cytoplasmic proteins that respond to a wide range of signals, including toxins, metal ions, and endogenous metabolites. Its best-characterized members share similar structural and functional features with the family founder, the mercury sensor MerR, although most of them do not respond to metal ions. The group of "canonical" MerR homologs displays common molecular mechanisms for controlling the transcriptional activation of their target genes in response to inducer signals. This includes the recognition of distinctive operator sequences located at suboptimal σ70 -dependent promoters. Interestingly, an increasing number of proteins assigned to the MerR family based on their DNA-binding domain do not match in structure, sequence, or mode of action with any of the canonical MerR-like regulators. Here, we analyzed several members of the family, including this last group. Based on a phylogenetic analysis, and similarities in structural/functional features and position of their target operators relative to the promoter elements, we propose to assign these "atypical/divergent" MerR regulators to a phylogenetically separated group. These atypical/divergent homologs represent a new class of transcriptional regulators with novel regulatory mechanisms.