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Hfq is a critical component of post-transcriptional regulatory networks in most bacteria. It usually functions as a chaperone for base-pairing small RNAs, although non-canonical regulatory roles are continually emerging. We have previously shown that Hfq represses IS 10/ Tn 10 transposase expression through both antisense RNA-dependent and independent mechanisms. In the current work, we set out to define the regulatory role of Hfq in the absence of the IS 10 antisense RNA. We show here that an interaction between the distal surface of Hfq and the ribosome-binding site of transposase m RNA ( RNA-IN) is required for repressing translation initiation. Additionally, this interaction was critical for the in vivo association of Hfq and RNA-IN. Finally, we present evidence that the small RNA ChiX activates transposase expression by titrating Hfq away from RNA-IN. The current results are considered in the broader context of Hfq biology and implications for Hfq titration by ChiX are discussed. [ABSTRACT FROM AUTHOR]

BSTRACT: The Central Nebraska Basins (NAWQA) study unit includes the Platte River and two major tributaries, the Loup and Elkhorn Rivers. Platte River flows are variable in the western part of the study unit because of diversions, but the Loup and Elkhorn Rivers originate in an area of dune sand covered by grassland that generates consistent base flows. More frequent runoff in the eastern part of the study unit also sustains stream flow. Ground water in the study unit has no regional confining units and the system is a water table aquifer throughout. Macroinvertebrate and fish taxa at biological sampling sites in the state were related to stream flow. One of the four wetland complexes identified in the study unit includes habitat for threatened and endangered bird species. The study unit is an agricultural area that includes row crops, both irrigated and nonirrigated in the eastern and southern parts, and rangeland in the Sand Hills of the western part. A water quality assessment will be based on the differences in environmental setting in each of four subunits within the study unit.] [ABSTRACT FROM AUTHOR]