Axon Development and Synapse Formation in Olfactory Sensory Neurons

The olfactory epithelium (OE) possesses the rare capacity among neuronal tissues to regenerate throughout life. As a result, progenitor cells continuously proliferate and differentiate into olfactory sensory neurons (OSNs) that project their axons to the olfactory bulb (OB) where they establish connections to the central nervous system. The olfactory epithelium is therefore an attractive model for the study of axonal growth and synapse formation. The present set of studies attempts to provide insights into synapse formation and axonal development of olfactory sensory neurons. First, I sought to understand the regulation of expression of pre-synaptic molecules in the olfactory epithelium. I established by in situ hybridization that as OSNs mature, they express sequentially groups of pre-synaptic genes. Genes encoding for proteins that play a structural role at the active zone showed an early onset of expression, whereas genes encoding for proteins associated with synaptic vesicles showed a later onset of expression. In particular, the signature molecule for glutamatergic neurons VGLUT2 shows the latest onset of expression. The sequential onset of expression suggests the existence of discrete steps in pre-synaptic development. In addition, contact with the targets in the olfactory bulb is not controlling pre-synaptic protein gene expression, suggesting that olfactory sensory neurons follow an intrinsic program of development. Second, in order to visualize simultaneously OSN axonal arborizations and their pre-synaptic specializations in vivo, I developed a method based on post-natal electroporation of the mouse nasal cavity. This technique allowed me to perform a temporal study where I followed the elaboration of axons and synapses in olfactory sensory neurons at different post-natal ages. The results show that olfactory sensory axons develop with exuberant growth and synapse formation. Exuberant branches and synapses are eliminated to achieve the mature pattern of connectivity in a process likely to be regulated by neural activity. Finally I investigated the consequences of suppressing neural activity in olfactory sensory neuron axonal morphology and synaptic composition. To this end I utilized two anosmic mouse models: cyclic nucleotide gated (CNG) channel and adenylyl cyclase 3 (AC3) knock-out mice. I observed that in the CNG knock-out mice, where OSNs do not generate action potentials after odor stimulation, the morphology of terminal arborizations and the synaptic composition were indistinguishable from wild-type littermates. In sharp contrast, AC3 knock-out mice, where there is no induction of cAMP production after odor stimulation, both the morphology and synaptic composition of OSN axons are severely altered. These results provide evidence that, unlike odor-induced membrane depolarization, odor-induced cAMP signaling events are critical for axonal growth and synapse formation in OSNs

High-Throughput Microarray Detection of Vomeronasal Receptor Gene Expression in Rodents

We performed comprehensive data mining to explore the vomeronasal receptor (V1R and V2R) repertoires in mouse and rat using the mm5 and rn3 genome, respectively. This bioinformatic analysis was followed by investigation of gene expression using a custom designed high-density oligonucleotide array containing all of these receptors and other selected genes of interest. This array enabled us to detect the specific expression of V1R and V2Rs which were previously identified solely based on computational prediction from gene sequence data, thereby establishing that these genes are indeed part of the vomeronasal system, especially the V2Rs. One hundred sixty-eight V1Rs and 98 V2Rs were detected to be highly enriched in mouse vomeronasal organ (VNO), and 108 V1Rs and 87 V2Rs in rat VNO. We monitored the expression profile of mouse VR genes in other non-VNO tissues with the result that some VR genes were re-designated as VR-like genes based on their non-olfactory expression pattern. Temporal expression profiles for mouse VR genes were characterized and their patterns were classified, revealing the developmental dynamics of these so-called pheromone receptors. We found numerous patterns of temporal expression which indicate possible behavior-related functions. The uneven composition of VR genes in certain patterns suggests a functional differentiation between the two types of VR genes. We found the coherence between VR genes and transcription factors in terms of their temporal expression patterns. In situ hybridization experiments were performed to evaluate the cell number change over time for selected receptor genes

DNA sequence variation of drought-response candidate genes in Austrocedrus chilensis

Background: Austrocedrus chilensis (D. Don) Pic. Ser. et Bizzarri commonly known as Patagonian cypress is a member of the Cupressaceae family, characterized by a high adaptive potential for growing in marginal areas and good timber quality. The species grows over a wide area and under a wide range of rainfall. This study assessed adaptive genetic variation at SNP level in candidate genes involved in response to drought stress. Results: A total of 18 single nucleotide polymorphisms (SNPs) were found among 1,428 bp. Average nucleotide diversity value (π = 0.00312) was similar to those previously reported in other Cupressaceae. The Fst average among genes and populations was 0.163 and the lowest differentiation was observed in continuous and humid populations. A number of neutrality tests were applied to find evidence of positive selection in our candidate gene set, but only AcAQP2 gene in Pedregoso and San Ramón populations revealed significant departures from neutrality with positive values suggesting balancing selection. Conclusions: In this study we report the levels of nucleotide diversity searched in some drought stress candidate genes in Austrocedrus chilensis and the selective factors that may be acting on this species.Fil: Pomponio, Maria Florencia. Instituto Nacional de Tecnologia Agropecuaria. Centro Nacional de Inv. Agropecuarias. Centro de Invest.de Recursos Naturales. Instituto de Recursos Biologicos; ArgentinaFil: Torales, Susana. Instituto Nacional de Tecnologia Agropecuaria. Centro Nacional de Inv. Agropecuarias. Centro de Invest.de Recursos Naturales. Instituto de Recursos Biologicos; ArgentinaFil: Gallo, Leonardo. Instituto Nacional de Tecnologia Agropecuaria. Centro Reg.patagonia Norte. Estacion Exptal.agrop.s.c.de Bariloche. Grupo de Genetica Forestal; ArgentinaFil: Pastorino, Mario Juan. Instituto Nacional de Tecnologia Agropecuaria. Centro Reg.patagonia Norte. Estacion Exptal.agrop.s.c.de Bariloche. Grupo de Genetica Forestal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marchelli, Paula. Instituto Nacional de Tecnologia Agropecuaria. Centro Reg.patagonia Norte. Estacion Exptal.agrop.s.c.de Bariloche. Grupo de Genetica Forestal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cervera, María Teresa. Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria. Centro de Investigación Forestal; EspañaFil: Marcucci Poltri, Susana Noemí. Instituto Nacional de Tecnologia Agropecuaria. Centro Nacional de Inv. Agropecuarias. Centro de Invest.de Cs.veterinarias y Agronomicas. Instituto de Biotecnologia; Argentin

De novo assembly and characterization of leaf transcriptome for the development of functional molecular markers of the extremophile multipurpose tree species Prosopis alba

Background: Prosopis alba (Fabaceae) is an important native tree adapted to arid and semiarid regions of north-western Argentina which is of great value as multipurpose species. Despite its importance, the genomic resources currently available for the entire Prosopis genus are still limited. Here we describe the development of a leaf transcriptome and the identification of new molecular markers that could support functional genetic studies in natural and domesticated populations of this genus. Results: Next generation DNA pyrosequencing technology applied to P. alba transcripts produced a total of 1,103,231 raw reads with an average length of 421 bp. De novo assembling generated a set of 15,814 isotigs and 71,101 non-assembled sequences (singletons) with an average of 991 bp and 288 bp respectively. A total of 39,000 unique singletons were identified after clustering natural and artificial duplicates from pyrosequencing reads. Regarding the non-redundant sequences or unigenes, 22,095 out of 54,814 were successfully annotated with Gene Ontology terms. Moreover, simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs) were searched, resulting in 5,992 and 6,236 markers, respectively, throughout the genome. For the validation of the the predicted SSR markers, a subset of 87 SSRs selected through functional annotation evidence was successfully amplified from six DNA samples of seedlings. From this analysis, 11 of these 87 SSRs were identified as polymorphic. Additionally, another set of 123 nuclear polymorphic SSRs were determined in silico, of which 50% have the probability of being effectively polymorphic. Conclusions: This study generated a successful global analysis of the P. alba leaf transcriptome after bioinformatic and wet laboratory validations of RNA-Seq data. The limited set of molecular markers currently available will be significantly increased with the thousands of new markers that were identified in this study. This information will strongly contribute to genomics resources for P. alba functional analysis and genetics. Finally, it will also potentially contribute to the development of population-based genome studies in the genera.Fil: Torales, Susana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; ArgentinaFil: Rivarola, Maximo Lisandro. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pomponio, María Florencia. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; ArgentinaFil: González, Sergio Alberto. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Acuña, Cintia Vanesa. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fernández, Paula del Carmen. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: López Lauenstein, Diego. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Verga, Aníbal Ramón. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Geneticos Vegetales; ArgentinaFil: Hopp, Horacio Esteban. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Paniego, Norma Beatriz. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marcucci Poltri, Susana Noemí. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentin

De novo transcriptome sequencing and SSR markers development for Cedrela balansae C. DC., a native tree species of northwest Argentina

The endangered Cedrela balansae C.DC. (Meliaceae) is a high-value timber species with great potential for forest plantations that inhabits the tropical forests in Northwestern Argentina. Research on this species is scarce because of the limited genetic and genomic information available. Here, we explored the transcriptome of C. balansae using 454 GS FLX Titanium next-generation sequencing (NGS) technology. Following de novo assembling, we identified 27,111 non-redundant unigenes longer than 200 bp, and considered these transcripts for further downstream analysis. The functional annotation was performed searching the 27,111 unigenes against the NR-Protein and the Interproscan databases. This analysis revealed 26,977 genes with homology in at least one of the Database analyzed. Furthermore, 7,774 unigenes in 142 different active biological pathways in C. balansae were identified with the KEGG database. Moreover, after in silico analyses, we detected 2,663 simple sequence repeats (SSRs) markers. A subset of 70 SSRs related to important “stress tolerance” traits based on functional annotation evidence, were selected for wet PCR-validation in C. balansae and other Cedrela species inhabiting in northwest and northeast of Argentina (C. fissilis, C. saltensis and C. angustifolia). Successful transferability was between 77% and 93% and thanks to this study, 32 polymorphic functional SSRs for all analyzed Cedrela species are now available. The gene catalog and molecular markers obtained here represent a starting point for further research, which will assist genetic breeding programs in the Cedrela genus and will contribute to identifying key populations for its preservation.Fil: Torales, Susana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; ArgentinaFil: Rivarola, Maximo Lisandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Gonzalez, Sergio. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Inza, María Virginia. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; ArgentinaFil: Pomponio, María Florencia. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; ArgentinaFil: Fernández, Paula. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Acuña, Cintia Vanesa. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zelener, Noga. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; ArgentinaFil: Fornes, Luis Fernando. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucuman-Santiago del Estero; ArgentinaFil: Hopp, Horacio Esteban. Universidad de Belgrano. Facultad de Ciencias Exactas y Naturales; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Paniego, Norma Beatriz. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marcucci Poltri, Susana Noemí. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentin

Transcriptome survey of Patagonian southern beech Nothofagus nervosa (= N. Alpina): assembly, annotation and molecular marker discovery

Nothofagus nervosa is one of the most emblematic native tree species of Patagonian temperate forests. Here, the shotgun RNA-sequencing (RNA-Seq) of the transcriptome of N. nervosa, including de novo assembly, functional annotation, and in silico discovery of potential molecular markers to support population and associations genetic studies, are described.Fil: Torales, Susana Leonor. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Rivarola, Maximo Lisandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pomponio, Maria Florencia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Fernandez, Paula Del Carmen. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Acuña, Cintia Vanesa. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Marchelli, Paula Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. ArgentinaFil: Gonzalez, Sergio Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Azpilicueta, María M. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. ArgentinaFil: Hopp, Horacio Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Gallo, Leonardo A. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. ArgentinaFil: Paniego, Norma Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marcucci Poltri, Susana Noemi. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentin

Tyrosine kinase c-Src constitutes a bridge between cystic fibrosis transmembrane regulator channel failure and MUC1 overexpression in cystic fibrosis

Fil: González Guerrico, Anatilde M. Instituto de Investigaciones Bioquı́micas Fundación Campomar (UBA, CONICET), 1405 Buenos Aires; Argentina.Fil: Cafferata, Eduardo. ANLIS Dr.C.G.Malbrán. Centro Nacional de Genética Médica; Argentina.Fil: Radrizzani, Martín. ANLIS Dr.C.G.Malbrán. Centro Nacional de Genética Médica; Argentina.Fil: Marcucci, Florencia. Instituto de Investigaciones Bioquı́micas Fundación Campomar (UBA, CONICET), 1405 Buenos Aires; Argentina.Fil: Gruenert, Dieter. Human Molecular Genetics Unit, Department of Medicine, University of Vermont, Burlington; Estados Unidos.Fil: Pivetta, Omar H. ANLIS Dr.C.G.Malbrán. Centro Nacional de Genética Médica; Argentina.Fil: Favaloro, Roberto R. Fundación Favaloro, 1093 Buenos Aires; Argentina.Fil: Laguens, Rubén. Fundación Favaloro, 1093 Buenos Aires; Argentina.Fil: Perrone, Sergio V. Fundación Favaloro, 1093 Buenos Aires; Argentina.Fil: Gallo, Guillermo C. Hospital de Pediatrı́a Prof. Dr. Juan P. Garrahan, 1425 Buenos Aires; Argentina.Fil: Santa-Coloma, Tomás A. Instituto de Investigaciones Bioquı́micas Fundación Campomar (UBA, CONICET), 1405 Buenos Aires; Argentina.Cystic fibrosis (CF), a disease caused by mutations in the cystic fibrosis transmembrane regulator (CFTR) chloride channel, is associated in the respiratory system with the accumulation of mucus and impaired lung function. The role of the CFTR channel in the regulation of the intracellular pathways that determine the overexpression of mucin genes is unknown. Using differential display, we have observed the differential expression of several mRNAs that may correspond to putative CFTR-dependent genes. One of these mRNAs was further characterized, and it corresponds to the tyrosine kinase c-Src. Additional results suggest that c-Src is a central element in the pathway connecting the CFTR channel with MUC1 overexpression and that the overexpression of mucins is a primary response to CFTR malfunction in cystic fibrosis, which occurs even in the absence of bacterial infection

Identification of single nucleotide polymorphisms [SNPs] at candidate genes involved in abiotic stress in two Prosopis species and hybrids

Aim of the study: Identify and compare SNPs on candidate genes related to abiotic stress in Prosopis chilensis, Prosopis flexuosa and interspecific hybrids Area of the study: Chaco árido, Argentina. Material and Methods: Fragments from 6 candidate genes were sequenced in 60 genotypes. DNA polymorphisms were analyzed. Main Results: The analysis revealed that the hybrids had the highest rate of polymorphism, followed by P. flexuosa and P. chilensis, the values found are comparable to other forest tree species. Research highlights: This approach will help to study genetic diversity variation on natural populations for assessing the effects of environmental changes.Fil: Marcucci Poltri, Susana Noemi. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Lopez Lauenstein, Diego. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Torales, Susana Leonor. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Pomponio, Maria Florencia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentin

Characterisation and transferability of transcriptomic microsatellite markers for Nothofagus species

Discriminant molecular markers are required for research on population genetics, as well as evolutionary studies involving identification of hybrids and parental species, or detection of the genome regions under selection. We provide a set of 27 transcriptomic microsatellite markers (SSRs) for South American Nothofagus species, derived from 73 Nothofagus alpina (=N. nervosa) annotated unigenes. Rates of cross-amplification ranged from 22% to 37%. Genetic characterisation of 22 transcriptomic SSRs for N. alpina and N. obliqua reveals low genetic variability, due to the general occurrence of one major allele at each locus, and high specificity, with few alleles shared between species (14%). At inter-species level 95% of loci were discriminant, with a total G''st over loci of 0.9, indicating that alleles were mostly fixed for all loci in both species. At intra-species level the number of markers with significant differentiation was 2.5 times higher for N. obliqua than for N. alpina populations. Moreover, transcriptomic SSRs showed higher performance compared with published anonymous microsatellites isolated from genome sequences without annotation. This set of transcriptomic microsatellites will be useful to the scientific community working on conservation and evolutionary aspects of Nothofagus species.Fil: El Mujtar, Verónica Andrea. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: López, María Gabriela. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Amalfi, Sabrina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pomponio, María Florencia. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; ArgentinaFil: Marcucci Poltri, Susana Noemí. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Torales, Susana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; Argentin

The expression of the mitochondrial encoded gene ND4 is downregulated in cystic fibrosis

Abstract: Cystic fibrosis (CF) is a disease produced by mutations in the CFTR channel. We have previously reported that the CFTR chloride transport activity regulates the differential expression of several genes, including SRC. Here we report that MT-ND4, a mitochondrial gene encoding a subunit of the mitochondrial Complex I (mtCx-I), is also a CFTR-dependent gene. A reduced expression of MT-ND4 was observed in CFDE cells (derived from a CF patient) when compared to CFDE cells ectopically expressing wild type CFTR. The differential expression of MT-ND4 in CF was confirmed by PCR. In situ hybridizations of deparaffinized human lung tissue slices derived from wt-CFTR or CF patients also showed downregulation of ND4 in CF. In addition, glibenclamide or CFTR(inh)-172 (CFTR chloride transport inhibitors) reduced MT-ND4 expression in cells expressing wt CFTR. These results suggest that the CFTR chloride transport activity indirectly up-regulates MT-ND4 expression