Search

Abstract The risk of developing drug addiction is strongly influenced by the epigenetic landscape and chromatin remodeling. While histone modifications such as methylation and acetylation have been studied in the ventral tegmental area and nucleus accumbens (NAc), the role of H2A monoubiquitination remains unknown. Our investigations, initially focused on the scaffold protein melanoma-associated antigen D1 (Maged1), reveal that H2A monoubiquitination in the paraventricular thalamus (PVT) significantly contributes to cocaine-adaptive behaviors and transcriptional repression induced by cocaine. Chronic cocaine use increases H2A monoubiquitination, regulated by Maged1 and its partner USP7. Accordingly, Maged1 specific inactivation in thalamic Vglut2 neurons, or USP7 inhibition, blocks cocaine-evoked H2A monoubiquitination and cocaine locomotor sensitization. Additionally, genetic variations in MAGED1 and USP7 are linked to altered susceptibility to cocaine addiction and cocaine-associated symptoms in humans. These findings unveil an epigenetic modification in a non-canonical reward pathway of the brain and a potent marker of epigenetic risk factors for drug addiction in humans.

Hydra regenerate various body parts on amputation by activation of the appropriate organiser, but how head formation is controlled is unclear. Here, the authors identify the transcription factor Sp5 as restricting head formation, by being activated by beta-catenin and then acting as a repressor of Wnt3.

Abstract Background The transcriptional activation of HoxD genes during mammalian limb development involves dynamic interactions with two topologically associating domains (TADs) flanking the HoxD cluster. In particular, the activation of the most posterior HoxD genes in developing digits is controlled by regulatory elements located in the centromeric TAD (C-DOM) through long-range contacts. Results To assess the structure–function relationships underlying such interactions, we measured compaction levels and TAD discreteness using a combination of chromosome conformation capture (4C-seq) and DNA FISH. We assessed the robustness of the TAD architecture by using a series of genomic deletions and inversions that impact the integrity of this chromatin domain and that remodel long-range contacts. We report multi-partite associations between HoxD genes and up to three enhancers. We find that the loss of native chromatin topology leads to the remodeling of TAD structure following distinct parameters. Conclusions Our results reveal that the recomposition of TAD architectures after large genomic re-arrangements is dependent on a boundary-selection mechanism in which CTCF mediates the gating of long-range contacts in combination with genomic distance and sequence specificity. Accordingly, the building of a recomposed TAD at this locus depends on distinct functional and constitutive parameters.

In all tetrapods examined thus far, the development and patterning of limbs require the activation of gene members of the HoxD cluster. In mammals, they are regulated by a complex bimodal process that controls first the proximal patterning and then the distal structure. During the shift from the former to the latter regulation, this bimodal regulatory mechanism allows the production of a domain with low Hoxd gene expression, at which both telomeric (T-DOM) and centromeric regulatory domains (C-DOM) are silent. These cells generate the future wrist and ankle articulations. We analyzed the implementation of this regulatory mechanism in chicken, i.e., in an animal for which large morphological differences exist between fore- and hindlimbs. We report that although this bimodal regulation is globally conserved between the mouse and the chick, some important modifications evolved at least between these two model systems, in particular regarding the activity of specific enhancers, the width of the TAD boundary separating the two regulations, and the comparison between the forelimb versus hindlimb regulatory controls. At least one aspect of these regulations seems to be more conserved between chick and bats than with mouse, which may relate to the extent to which forelimbs and hindlimbs of these various animals differ in their morphologies.

Mediterranean Temporary Ponds (MTPs) represent a priority habitat according to Directive 92/43/EEC (Natura 2000 code: 3170*). These are very shallow water habitats only seasonally flooded, with a flora mainly composed of Mediterranean therophytic and geophytic species. Its extreme seasonality and small size make this habitat highly vulnerable and hard to manage. In recent Italian monitoring campaigns, the conservation status of MTP 3170* was considered inadequate. In Apulia, where the habitat is considered as “the most vulnerable type”, 73 sites were censused, with a total coverage of about 10,000 m2. The present work refers to the monitoring for three years of a total of 16 habitat 3170* sites, with the aim of better describing faunal indicator species for this priority habitat. A total of 158 taxa of flora and 103 of fauna were identified from 54 floristic and 44 faunistic samplings in total, with a robust updating of the listed biodiversity. For the first time a group of faunal species is proposed as an indicator of the habitat MTP 3170*. The conservation status, assessed on the basis of structural and functional criteria, gave a satisfactory status for seven sites and an unsatisfactory one (variously rated as inadequate or bad) for nine.

This paper presents the validation of 16 new associations, described in a previous contribution, for the temporary ponds of the class Isoeto-Nanojuncetea in Apulia (southern Italy).

The ephemeral hygrophilous vegetation occurring in the temporary ponds of Apulia (southern Italy) weres studied following the phytosociological approach. On the base of 153 phytosociological relevés carried out during the period 2015-2018, 19 associations were identified, of which 16 described for the first time. All the associations belong to the Isoeto-Nanojuncetea class. The surveyed associations can be arranged in two orders, such as Isoetetalia, including those with a winter-spring cycle and Nanocyperetalia, regarding those with a summertime cycle. The identified association has been examined in detail, and for each one, we provided a phytosociological table. The communities belonging to the Isoetetalia are 17 and arranged in four alliances (Isoetion, Preslion cervinae, Cicendio filiformis-Solenopsion laurentiae, Agrostion salmanticae); instead, those ones of Nanocyperetalia are two both included in the Verbenion supinae. In order to highlight the relationships among the associations, all the relevés used for this investigation are processed. Overall, this analysis confirms the autonomy of the associations, grouping them according to the syntaxonomic arrangement proposed by the authors. Taxonomic investigations on the flora occurring in these habitats allowed the detection of two new subspecies of Solenopsis laurentia, both with a different autoecology.

In this contribution, new data concerning the distribution of native vascular flora in Italy are presented. It includes new records, confirmations, exclusions, and status changes to the Italian administrative regions for taxa in the genera Ajuga, Chamaemelum, Clematis, Convolvulus, Cytisus, Deschampsia, Eleocharis, Epipactis, Euphorbia, Groenlandia, Hedera, Hieracium, Hydrocharis, Jacobaea, Juncus, Klasea, Lagurus, Leersia, Linum, Nerium, Onopordum, Persicaria, Phlomis, Polypogon, Potamogeton, Securigera, Sedum, Soleirolia, Stachys, Umbilicus, Valerianella, and Vinca. Nomenclatural and distribution updates, published elsewhere, and corrigenda are provided as Suppl. material 1.