Knockdown of a zebrafish aryl hydrocarbon receptor repressor (ahrra) affects expression of genes related to photoreceptor development and hematopoiesis.

ABSTRACT: The aryl hydrocarbon receptor repressor (AHRR) is a bHLH-PAS protein closely related to the aryl hydrocarbon receptor (AHR). AHRR is a transcriptional repressor of AHR and hypoxia-inducible factor (HIF) and is regulated by an AHR-dependent mechanism. Zebrafish possess two AHRR paralogs; AHRRa regulates constitutive AHR signaling during development, while AHRRb regulates polyaromatic hydrocarbon-induced gene expression. However, very little is known about the endogenous roles of AHRRs in development and physiology. The objective of this study was to elucidate the role of AHRRs during zebrafish development using a loss-of-function approach followed by microarray analysis. Zebrafish embryos were microinjected with morpholino oligonucleotides (MO) against AHRRa or AHRRb to disrupt endogenous signaling during development. At 72 hours post-fertilization (hpf), embryos were sampled for microarray analysis. Agilent microarray analysis revealed altered expression of 279 and 116 genes with knockdown of AHRRa and AHRRb, respectively. In AHRRa-morphant embryos, 97 genes were up-regulated and 182 genes were down-regulated. Among the differentially expressed genes were a large number related to photoreceptor development, including cone-specific genes such as short-wave, medium-wave and long-wave sensitive opsins (opn1sw1, opn1sw2, opn1mw1, opn1lw2), phosphodiesterases (pde6H, pde6C), retinol binding protein (rbp4l), phosducin, and arrestin. These results suggest that AHRRa may be involved in photoreceptor development. In addition, AHRRa knockdown also caused up-regulation of embryonic hemoglobin (hbbe3), suggesting a role for AHRR in regulating hematopoiesis. Knockdown of AHRRb caused up-regulation of 31 genes and down-regulation of 85 genes, without enrichment of genes related to any specific biological process. Overall, these results suggest that AHRRs play multiple roles during development. Three different treatment conditions (Control-MO, AHRRa-MO and AHRRb-MO) and two replicates per treatment

ORGANISM(S): Danio rerio

SUBMITTER: Neelakanteswar Aluru 

PROVIDER: E-GEOD-52229 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress