In principle, Cefdinir proteins in aggregates or inclusion bodies could appear to be localized in one or more foci, and it is possible that some of the clones isolated from the screen have localized GFP signal due to aggregation or inclusion body formation. However, potential aggregation or inclusion body LOUREIRIN-B formation due to protein over-production was limited for the screen used here, because proteins were produced from their wild-type promoter at the normal chromosomal locus. In addition, the foci of CheR, AhpC, and CC3691 were not caused by aggregation of truncated GFPfusion proteins, or by dimerization or aggregation of the GFP sequence, because identical patterns were seen with full-length versions of the proteins fused to the M2 epitope. A mutagenesis-based screen such as the one used here is significantly faster and less expensive than constructing fusions for each gene, and because the same localization patterns were observed for fusions of full-length versions of five of the proteins to M2 or GFP, the results for many proteins would be identical. However, the mutagenesis approach will clearly miss some localized proteins. Because Tn5 clearly has some sequence bias for insertion, the recovery of localized proteins could be expanded by using additional transposons, such as mariner and mu, engineered to insert gfp. Proteins that are essential and cannot tolerate a Cterminal fusion, and proteins that require a free C terminus for localization will not be recovered using transposon mutagenesis. Polar effects caused by transposon insertion may also prevent recovery of some localized proteins. Nevertheless, many new localized proteins can be found with this technique. Brain-derived neurotrophic factor and neurotrophin-4 are two naturally occurring ligands for the receptor tyrosine kinase trkB. Originally viewed as trophic factors for neuronal survival and neurite outgrowth during embryonic development, these factors can actually exert a wide range of biological functions in the adult, such as long term potentiation and synaptic plasticity. The mRNA of BDNF is normally expressed in the ventromedial hypothalamus. The VMH expression of BDNF mRNA is reduced under several conditions where the appetite is increased, such as food deprivation, melanocortin antagonism and genetic ablation of melanocortin 4 receptor. The loss-of-function mutations of BDNF or trkB loci in mice led to a syndrome of hyperphagia and obesity.