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Capicua (Cic) proteins are conserved HMG-box transcriptional repressors that control receptor tyrosine kinase (RTK) signaling responses and are implicated in human neurological syndromes and cancer. While Cic is known to exist as short (Cic-S) and long (Cic-L) isoforms with identical HMG-box and associated core regions but distinct N termini, most previous studies have focused on Cic-S, leaving the function of Cic-L unexplored. Here we show that Cic-L acts in two capacities during

Capicua (Cic) proteins are conserved HMG-box transcriptional repressors that control receptor tyrosine kinase (RTK) signaling responses and are implicated in human neurological syndromes and cancer. While Cic is known to exist as short (Cic-S) and long (Cic-L) isoforms with identical HMG-box and associated core regions but distinct N termini, most previous studies have focused on Cic-S, leaving the function of Cic-L unexplored. Here we show that Cic-L acts in two capacities during Drosophila oogenesis: 1) as a canonical sensor of RTK signaling in somatic follicle cells, and 2) as a regulator of postmitotic growth in germline nurse cells. In these latter cells, Cic-L behaves as a temporal signal that terminates endoreplicative growth before they dump their contents into the oocyte. We show that Cic-L is necessary and sufficient for nurse cell endoreplication arrest and induces both stabilization of CycE and down-regulation of Myc. Surprisingly, this function depends mainly on the Cic-L–specific N-terminal module, which is capable of acting independently of the Cic HMG-box–containing core. Mirroring these observations, basal metazoans possess truncated Cic-like proteins composed only of Cic-L N-terminal sequences, suggesting that this module plays unique, ancient roles unrelated to the canonical function of Cic., This work was funded by the Spanish Government (grants BFU2014-52863-P, BFU2017-87244-P, and PID2020-119248GB-I00), the Generalitat de Catalunya (Grant 2017 SGR 475), and the NIH (Grant GM141843). L.R.-M. and C.L. were supported by predoctoral contracts from the Spanish Government.

14 pages, 4 figures, 2 tables, supplementary information https://doi.org/10.1038/s41598-022-13941-4.-- Data availability: The datasets generated and/or analysed during the current study are available in the GenBank repository, accession numbers: OM241982–OM242947, An interesting evolutionary question that still remains open is the connectivity between marine populations. Marine currents can favour the dispersal of larvae or adults, but they can also produce eddies and gyres generating oceanographic fronts, thus limiting gene flow. To address this subject, we selected the Atlantic-Mediterranean transition, where several fronts are located: Gibraltar Strait (GS), Almeria-Oran Front (AOF) and Ibiza Channel (IC). Seven populations of the marine crab Liocarcinus depurator (Cadiz, West and East Alboran, Alacant, Valencia, Ebro Delta and North Catalonia) located along this transition were analysed in six consecutive years (2014–2019) using a fragment of the COI (Cytochrome Oxidase subunit I) gene. All sequences (966) belonged to two well defined haplogroups: ATL (most abundant in Atlantic waters) and MED (predominant in Mediterranean waters). Following a geographic variation, the frequency of ATL decreased significantly from Cadiz to North Catalonia. However, this variation presented steps due to the effect of oceanographic restrictions/fronts. Significant effects were recorded for GS (2015, 2017, 2018 and 2019), AOF (all years except 2018) and IC (2016). The intensity and precise location of these fronts changed over time. Multivariate analyses distinguished three main population groups: Cadiz, Alboran Sea and the remaining Mediterranean populations. These findings could be relevant to properly define Marine Protected Areas and for conservation and fisheries policies, This research was financially supported by the projects CTM2015-66400-C3-3-R founded by MINECO/FEDER, CTM2017‐88080 funded by the CIN/AEI/https://doi.org/10.13039/501100011033 and by ERDF 'A way of making Europe' of the European Union, the project PID2020-118550RB funded by the MCIN/AEI/https://doi.org/10.13039/501100011033 and by the project 2017SGR 1120 (Generalitat de Catalunya, Spain). Partial support was also provided by the Spanish Government through the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S) to the Institut de Ciències del Mar (ICM-CSIC)

Drosophila suzukii is native from East and Southeast Asia and spread very fast around the world being considered an invasive pest species. Many demographic, population genetics and genomics studies have been recently developed, but so far no analysis has been carried out regarding the presence of chromosomal inversions in D. suzukii natural populations. In this research, we studied polytene chromosomes of flies collected from the Font Groga (Barcelona) population. The chromosomes and many of their segments were characterized for their similarity with those from D. melanogaster. This is the report of one paracentric inversion (in heterozygous condition) in the right arm of the third chromosome (3R). As far as we know, it is the first time that an inversion has been observed in a D. suzukii natural population. Finally, the evolutionary significance of the finding of inversions in this species is discussed.