On the robustness of germ cell migration and microRNA-mediated regulation of chemokine signaling

Primordial Germ Cell Development in the Poeciliid, Gambusia holbrooki, Reveals Shared Features Between Lecithotrophs and Matrotrophs

“…However, its established role as an anchor for maternal RNAs in unfertilised eggs and polymerization of cortical microtubule arrays has been demonstrated in Xenopus ( Mei et al, 2013 ) needs verification in teleost. The subsequent occurrence of dnd in the embryonic and postnatal germline of G. holbrooki is consistent with those reported for other vertebrates ( Youngren et al, 2005 ; Aramaki et al, 2007 ) including teleosts ( Su et al, 2014 ; Duan et al, 2015 ; Wargelius et al, 2016 ) maintaining germline identity by protecting transcripts from miRNA-mediated decay ( Ketting, 2007 ; Goudarzi et al, 2013 ), facilitating translation of essential germ plasm components for PGC development ( Aguero et al, 2017 ), preventing PGCs from soma differentiation ( Weidinger et al, 2003 ; Gross-Thebing et al, 2017 ) and titrating the abundant mRNA through transcription silencing ( Nousch et al, 2013 ; Yamaji et al, 2017 ). Taken together, the exclusive expression of dnd-α in gambusia germ cells encoding the essential regulatory domains suggests a conserved role for it in germline maintenance in this species and likely in other poeciliids.…”

“…However, its established role as an anchor for maternal RNAs in unfertilised eggs and polymerization of cortical microtubule arrays has been demonstrated in Xenopus (Mei et al, 2013) needs verification in teleost. The subsequent occurrence of dnd in the embryonic and postnatal germline of G. holbrooki is consistent with those reported for other vertebrates (Youngren et al, 2005;Aramaki et al, 2007) including teleosts (Su et al, 2014;Duan et al, 2015;Wargelius et al, 2016) maintaining germline identity by protecting transcripts from miRNAmediated decay (Ketting, 2007;Goudarzi et al, 2013), FIGURE 7 | Comparative PGC development in representative lecithotrophic and matrotrophic species with increasing level of maternal care. In zebrafish (Raz, 2003;Eno and Pelegri, 2013) and G. holbrooki, PGC markers are compartmentalised in four distinct cells (red dots) by cleavage (8-cell and Cl4, respectively).…”

Mutation in cpsf6/CFIm68 (Cleavage and Polyadenylation Specificity Factor Subunit 6) causes short 3'UTRs and disturbs gene expression in developing embryos, as revealed by an analysis of primordial germ cell migration using the medaka mutant naruto

“…The proper gradient of SDF1 in the somatic environment is thought to be formed by another somatically expressed SDF1-receptor, CXCR7, promoting the internalization and degradation of SDF1 as a sequestration receptor [ 7 ]. miRNA-mediated post-transcriptional gene regulation of sdf1 and cxcr7 has also been indicated as facilitating proper gradient formation of SDF1 [ 8 – 10 ]. Research has shown that this SDF1-CXCR4 chemokine signaling plays an important role in the regulation of migration and colonization of PGCs to the gonads not only in fish but also in a wide variety of vertebrates such as mice [ 11 ], chickens [ 12 ] and frogs [ 13 ].…”

Chemokine signaling in development and disease

“…In mice and zebrafish, PGCs express the CXCR4 or zf Cxcr4b receptor (zebrafish genes/proteins will be indicated by the prefix zf ), respectively, and closely follow dynamically changing sources of CXCL12/zf Cxcl12a Doitsidou et al, 2002;Knaut et al, 2003;Molyneaux et al, 2003). During PGC migration in zebrafish, changes in zf cxcl12a promoter activity are mirrored by similar dynamics on the transcript and protein level through microRNA-mediated zf cxcl12a transcript degradation (Staton et al, 2011), which remains controversial (Goudarzi et al, 2013;Staton et al, 2013), and through zf Cxcr7b-mediated zf Cxcl12a protein clearance (Boldajipour et al, 2008).…”