Midbrain dopamine (mDA) neurons play critical roles in the regulation of voluntary movement and their dysfunction is associated with Parkinson’s disease. Pitx3 has been implicated in the proper development of mDA neurons in the substantia nigra pars compacta, which are selectively lost in Parkinson’s disease. However, the basic mechanisms underlying its role in mDA neuron development and/or survival are poorly understood. Toward this goal, we sought to identify downstream target genes of Pitx3 by comparing gene expression profiles in mDA neurons of wild-type and Pitx3-deficient aphakia mice. This global gene expression analysis revealed many potential target genes of Pitx3; in particular, the expression of vesicular monoamine transporter 2 and dopamine transporter, responsible for dopamine storage and reuptake, respectively, is greatly reduced in mDA neurons by Pitx3 ablation. In addition, gain-of-function analyses and chromatin immunoprecipitation strongly indicate that Pitx3 may directly activate transcription of vesicular monoamine transporter 2 and dopamine transporter genes, critically contributing to neurotransmission and/or survival of mDA neurons. As the two genes have been known to be regulated by Nurr1, another key dopaminergic transcription factor, we propose that Pitx3 and Nurr1 may coordinately regulate mDA specification and survival, at least in part, through a merging and overlapping downstream pathway.

Correction for ‘PAMAM/5-fluorouracil drug conjugate for targeting E6 and E7 oncoproteins in cervical cancer: a combined experimental/in silico approach’ by Arunkumar Rengaraj et al., RSC Adv., 2017, 7, 5046–5054.

In this study, fosmid cloning strategies were used to assess the microbial populations in water from the International Space Station (ISS) drinking water system (henceforth referred to as Prebiocide and Tank A water samples). The goals of this study were: to compare the sensitivity of the fosmid cloning strategy with that of traditional culture-based and 16S rRNA-based approaches and to detect the widest possible spectrum of microbial populations during the water purification process. Initially, microbes could not be cultivated, and conventional PCR failed to amplify 16S rDNA fragments from these low biomass samples. Therefore, randomly primed rolling-circle amplification was used to amplify any DNA that might be present in the samples, followed by size selection by using pulsed-field gel electrophoresis. The amplified high-molecular-weight DNA from both samples was cloned into fosmid vectors. Several hundred clones were randomly selected for sequencing, followed by Blastn/Blastx searches. Sequences encoding specific genes from Burkholderia, a species abundant in the soil and groundwater, were found in both samples. Bradyrhizobium and Mesorhizobium, which belong to rhizobia, a large community of nitrogen fixers often found in association with plant roots, were present in the Prebiocide samples. Ralstonia, which is prevalent in soils with a high heavy metal content, was detected in the Tank A samples. The detection of many unidentified sequences suggests the presence of potentially novel microbial fingerprints. The bacterial diversity detected in this pilot study using a fosmid vector approach was higher than that detected by conventional 16S rRNA gene sequencing.