Dynamic Hsp83 RNA Localization during Drosophila Oogenesis and Embryogenesis

Abstract

Hsp83 is the Drosophila homolog of the mammalian Hsp90 family of regulatory molecular chaperones. We show that maternally synthesized Hsp83 transcripts are localized to the posterior pole of the early Drosophila embryo by a novel mechanism involving a combination of generalized RNA degradation and local protection at the posterior. This protection of Hsp83 RNA occurs in wild-type embryos and embryos produced by females carrying the maternal effect mutations nanos and pumilio, which eliminate components of the posterior polar plasm without disrupting polar granule integrity. In contrast, Hsp83 RNA is not protected at the posterior pole of embryos produced by females carrying maternal mutations that disrupt the posterior polar plasm and the polar granules--cappuccino, oskar, spire, staufen, tudor, valois, and vasa. Mislocalization of oskar RNA to the anterior pole, which has been shown to result in induction of germ cells at the anterior, leads to anterior protection of maternal Hsp83 RNA. These results suggest that Hsp83 RNA is a component of the posterior polar plasm that might be associated with polar granules. In addition, we show that zygotic expression of Hsp83 commences in the anterior third of the embryo at the syncytial blastoderm stage and is regulated by the anterior morphogen, bicoid. We consider the possible developmental significance of this complex control of Hsp83 transcript distribution.

Sex‐ and caste‐specific transcriptomes of larval honey bee (Apis mellifera L.) gonads: DMRT A2 and Hsp83 are differentially expressed and regulated by juvenile hormone

“…As chaperones, HSPs are known to be highly expressed in response to environment stress, as well as to the presence of hormones (Xu, Xiao, Xia, Murphy, & Huang, 2010). Hsp83 has been associated with embryogenesis and oogenesis in D. melanogaster (Ding, Parkhurst, Halsell, & Lipshitz, 1993), and with the facilitation of nuclear import of the JH receptor Methoprene‐tolerant in the presence of JH, leading to Kr‐h1 expression (He et al, 2014). In a previous project we had found another member of the HSP family, Hsp90 , as highly expressed in larval queen ovaries and also as exhibiting a strong JH‐treatment response in larval worker ovaries (Lago et al, 2016).…”

The Identification and Functional Analysis of mRNA Localizing to Centrosomes

“…RNA localization occurs primarily through three distinct mechanisms: diffusion and entrapment, best exemplified by nanos mRNA in the Drosophila oocyte ( Forrest and Gavis, 2003 ); protection from degradation, as typified by Hsp83 mRNA in the Drosophila embryo ( Ding et al, 1993 ); or active transport, as observed for many RNAs, including ASH1 mRNA in budding yeast ( Long et al, 1997 ; Takizawa et al, 1997 ; Bertrand et al, 1998 ). Active transport involves the trafficking of a cargo, such as an RNP, connected via adaptor proteins to molecular motors, which translocate on actin or microtubule cytoskeletal tracks ( Bullock, 2011 ).…”

Massively parallel identification of mRNA localization elements in primary cortical neurons

“…For example, localization-dependent mRNA degradation has been described for Hsp83 and nanos. Their mRNAs are degraded throughout Drosophila eggs via the Smaug-mediated recruitment of deadenylation complex but remain stable at the posterior pole 54,55 . Previous studies reported local processing of miRNAs 56 and modification of the components of the miRNA pathway in response to synaptic activity [57][58][59] .…”