MTs play pivotal roles in physiological and redox homeostasis. They are also essential duringembryo development of P. lividus sea urchin. At least five MT genes are expressed in P.lividus embryo.MT7 and MT8 are constitutively expressed; while, MT4, 5, and 6 are considered asmetal-induced homologues. Whole mount in situ hybridization (WMISH) defined the MTmRNAs localization across the embryo territories of the sea urchin. At the gastrula stage,MT7 is localized principally in the endomesoderm, in the vegetal pole. Progressively, itbecomes heavily expressed in the endoderm during archenteron specialization in midgut andhindgut and then in stomach and intestine at the pluteus stage. In contrast, at the gastrula stageMT8 appears strictly localized in the oral ectoderm and in the ventral region of the ciliaryband. At the pluteus stage, it is mainly localized in a narrow strip of cells between the analarms of the larva (the boundary between oral and aboral ectoderm) and lightly in the oralectoderm.Inducible MTs are usually undetectable by WMISH albeit MT6 appeared at the pluteus stageonly in couples of cells at the tips of the elongating anterolateral and post-oral skeletal rods.After metal exposure, inducible MT expression is detected only in mesenchyme cells, nomatter where they were delocalized with respect to their correct arrangement in the blastocoelby the specific metal treatment. Interestingly, hybridisation signals appear punctiform,looking as grouped and anchored in specific structures or accumulated in vesicles. The PMCsindeed contain electron-dense granules (named calcein puncta) which correspond tocalcium-rich vesicles that contain nanospheres of calcium carbonate necessary for the larvalskeleton formation. A preliminary bioinformatics search for cis-acting localizing elements(zip-codes) and secondary structures recognized by RBPs is giving promising results for theunveiling of mechanisms leading to transcript localization.
|Numero di pagine||1|
|Stato di pubblicazione||Published - 2018|