Disease relevance of Nr2e1

• To characterize the Nr2e1 locus, which may also contain the mouse kidney disease (kd) allele, we compared sequence from human, mouse, and the puffer fish Fugu rubripes [1].
• Developmental eye abnormalities were also background-dependent with B6129F1-frc mice having less severe thinning of optic layers and less affected electroretinogram responses [2].
• Establishment and characterization of a mouse strain (TLL) that spontaneously develops T-cell lymphomas/leukemia [3].

High impact information on Nr2e1

• The similarities in structure, expression pattern, target gene specificity and phenotypes in transgenic flies suggest conservation of genetic programs upstream and downstream of this Tlx/Tll class of nuclear receptors during embryogenesis [4].
• Tlx acts as a proangiogenic switch by regulating extracellular assembly of fibronectin matrices in retinal astrocytes [5].
• In mice null for Tlx, retinal astrocytes maintain VEGF expression; however, the extracellular assembly of fibronectin matrices by astrocytes is severely impaired, leading to defective scaffold formation and a complete failure of normal retinal vascular development [5].
• Tlx expression by retinal astrocytes is controlled by oxygen concentration and rapidly downregulated upon contact with blood vessels [5].
• Subsequently, later-born (upper-layer) cortical neurons are specified in an Ngn-independent manner, requiring instead the synergistic activities of Pax6 and Tlx, which also control a binary choice between cortical/glutamatergic and subcortical/GABAergic fates [6].

Biological context of Nr2e1

• In these studies we show that hippocampal synaptic transmission appears normal in the dentate gyrus and cornu ammonis 1 subfields of adult mice that lack Nr2e1 (Nr2e1-/-), and that fEPSP shape, paired-pulse responses, and short-term plasticity are not substantially altered in either subfield [7].
• We find that Pax2 is a direct target and that the Tlx binding site in its promoter is conserved between mouse and human [8].
• The Tlx mutant phenotype is similar to, but less severe than, that seen in Small eye (i.e. Pax6) mutants [9].
• The patterning defects in the Tlx mutant telencephalon result in a loss of region-specific gene expression in the ventral-most pallial region [9].
• Tlx, an orphan nuclear receptor, regulates cell numbers and astrocyte development in the developing retina [10].

Anatomical context of Nr2e1

• Golgi analysis revealed that there was a significant reduction in both dendritic branching and dendritic length that was specific to dentate gyrus granule cells in the Nr2e1-/- mice [7].
• The spontaneous or targeted deletion of the nuclear receptor transcription factor Nr2e1 produces a mouse that shows hypoplasia of the hippocampal formation and reduced neurogenesis in adult mice [7].
• This work identifies Tlx as an essential component of the molecular network involved in the hypoxia-inducible proangiogenic switch in retinal astrocytes [5].
• The localized expression of the orphan nuclear receptor Tlx in the optic cup and discrete parts of the central nervous system suggested the possible role of Tlx in the formation or function of these structures [8].
• Analyses of Tlx targeted mice revealed that, in addition to the central nervous system cortical defects, lack of Tlx function results in progressive retinal and optic nerve degeneration with associated blindness [8].

Regulatory relationships of Nr2e1

• Tlx is expressed broadly in the ventricular zone, with the exception of the dorsomedial and ventromedial regions [9].

Other interactions of Nr2e1

• Finally, we investigated possible genetic interactions between Gsh2 and Tlx in lateral telencephalic development [11].
• Furthermore, we show that Tlx is expressed by immature astrocytes that migrate from the optic nerve onto the inner surface of the retina and is required for their generation and maturation, as assessed by honeycomb network formation and expression of R-cadherin, a critical component for vasculogenesis [10].
• Our studies indicate that PCs in the ventricular zone are sensitive to loss of Tlx in caudal regions only; however, PCs in the subventricular zone are altered at all rostrocaudal levels in tlx-deficient animals [12].
• Although the development of the Tlx mutant striatum is compromised, an apparently normal number of olfactory bulb interneurons are observed [11].

Analytical, diagnostic and therapeutic context of Nr2e1

• Comparative promoter and homeodomain sequence analyses suggest that it is related to the Hox11 gene, which belongs to the Tlx homeobox family [13].
• SDS-PAGE (sodium dodecyl sulphate-polyacrylamide gel electrophoresis) and Western blotting studies have shown that the Pseudonaja venoms contained proportionately more PA component than venoms of the Taipan (Oxyuranus scutellatus) or the Fierce snake (O. microlepidotus) [14].

References