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- Abu-Siniyeh, Ahmed, et al.
(författare)
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The aPKC/Par3/Par6 Polarity Complex and Membrane Order Are Functionally Interdependent in Epithelia During Vertebrate Organogenesis
- 2016
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Ingår i: Traffic. - : Wiley. - 1398-9219 .- 1600-0854. ; 17:1, s. 66-79
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Tidskriftsartikel (refereegranskat)abstract
- The differential distribution of lipids between apical and basolateral membranes is necessary for many epithelial cell functions, but how this characteristic membrane organization is integrated within the polarity network during ductal organ development is poorly understood. Here we quantified membrane order in the gut, kidney and liver ductal epithelia in zebrafish larvae at 3-11 days post fertilization (dpf) with Laurdan 2-photon microscopy. We then applied a combination of Laurdan imaging, antisense knock-down and analysis of polarity markers to understand the relationship between membrane order and apical-basal polarity. We found a reciprocal relationship between membrane order and the cell polarity network. Reducing membrane condensation by exogenously added oxysterol or depletion of cholesterol reduced apical targeting of the polarity protein, aPKC. Conversely, using morpholino knock down in zebrafish, we found that membrane order was dependent upon the Crb3 and Par3 polarity protein expression in ductal epithelia. Hence our data suggest that the biophysical property of membrane lipid packing is a regulatory element in apical basal polarity.
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| 2. |
- Sundström, Elisabeth, et al.
(författare)
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Identification of a melanocyte-specific, microphthalmia-associated transcription factor-dependent regulatory element in the intronic duplication causing hair greying and melanoma in horses
- 2012
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Ingår i: Pigment Cell & Melanoma Research. - 1755-1471 .- 1755-148X. ; 25:1, s. 28-36
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Tidskriftsartikel (refereegranskat)abstract
- Greying with age in horses is an autosomal dominant trait, characterized by hair greying, high incidence of melanoma and vitiligo-like depigmentation. Previous studies have revealed that the causative mutation for this phenotype is a 4.6-kb intronic duplication in STX17 (Syntaxin 17). By using reporter constructs in transgenic zebrafish, we show that a construct containing two copies of the duplicated sequence acts as a strong enhancer in neural crest cells and has subsequent melanophore-specific activity during zebrafish embryonic development whereas a single copy of the duplicated sequence acts as a weak enhancer, consistent with the phenotypic manifestation of the mutation in horses. We further used luciferase assays to investigate regulatory regions in the duplication, to reveal tissue-specific activities of these elements. One region upregulated the reporter gene expression in a melanocyte-specific manner and contained two microphthalmia-associated transcription factor (MITF) binding sites, essential for the activity. Microphthalmia-associated transcription factor regulates melanocyte development, and these binding sites are outstanding candidates for mediating the melanocyte-specific activity of the element. These results provide strong support for the causative nature of the duplication and constitute an explanation for the melanocyte-specific effects of the Grey allele.
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