Ribosomes are the cellular structures responsible for the synthesis of protein in all branches of life. All ribosomes are made from a large and small subunit that in turn are composed of protein and RNA. The synthesis of eukaryotic ribosomes is a complex process involving more than 200 factors and spans three cellular compartments: the nucleolus, the nucloplasm, and the cytoplasm. The precise function of most of these ribosome biogenesis factors remains unknown. The RNA component of ribosomes is in part processed from a large RNA transcript that yields most of the RNA present in mature ribosomes. Part of the maturation process involves modification of this ribosomal RNA as processing is carried out. Recent work constructing protein interaction networks in Saccharomyces cerevisiae suggested the methyltransferase Bud23 was involved in ribosome biogenesis (1). This thesis describes my work to characterize Bud23 and place it within the ribosome biogenesis pathway. Bud23 is a SAM methyltransferase important for the proper biogenesis of the small ribosomal subunit. Here I will demonstrate that Bud23 methylates G1575 of the small subunit ribosomal RNA (SSU rRNA), and its absence delays export of the SSU rRNA from the nucleolas, and the nucleus, and results in the delayed maturation of the SSU rRNA. Finally, I will show that Bud23 function is connected to small subunit processome factor Utp14 through identification of a Utp14 mutant that suppresses the bud23[Delta] deletion phenotype. / text

Το επιστημονικό ενδιαφέρον της παρούσας διδακτορικής διατριβής εστιάζεται στο ρόλο του κυτταροσκελετού της δεσμίνης (desmin), της μυοειδικής πρωτεΐνης, μέλος της οικογένειας των ενδιάμεσων ινιδίων, στη διατήρηση και τη λειτουργία του καρδιακού μυός. H καταστολή της έκφρασης της δεσμίνης σε μύες με τη χρησιμοποίηση της γονιδιακής στόχευσης, έδειξε πως η έκφραση της δεσμίνης είναι απαραίτητη για τη διατήρηση της λειτουργικής και δομικής ακεραιότητας του καρδιακού μυός. Μύες που δεν εκφράζουν δεσμίνη αναπτύσσουν διατατική καρδιομυοπάθεια, που χαρακτηρίζεται από ανωμαλίες σε υποκυτταρικά οργανίδια, όπως είναι τα μιτοχόνδρια, εκτεταμένη ίνωση και εναπόθεση ασβεστίου, με επακόλουθο τον κυτταρικό θάνατο, και τελικά την καρδιακή ανεπάρκεια. Πιο συγκεκριμένα σε μια προσπάθεια διερεύνησης της βιολογικής δράσης της δεσμίνης, μελετήθηκαν οι πρωτεϊνικές αλληλεπιδράσεις αυτού του μορίου. Η ανεύρεση μορίων με τα οποία η δεσμίνη αλληλεπιδρά μπορεί να δώσει σημαντικές πληροφορίες για τη βιολογικής της δράση και να βοηθήσει στην κατανόηση της παθολογίας που παρατηρείται σε επίμυς όπου έχει κατασταλεί η έκφρασή της (διαγονιδιακό μοντέλο διατατικής καρδιομυοπάθειας που έχει δημιουργηθεί από το εργαστήριό μας, des-/-) ή σε ασθενείς με καρδιομυοπάθειες εξαιτίας μεταλλαγών στο μόριο της δεσμίνης. Για το σκοπό αυτό εφαρμόστηκε η μέθοδος του διυβριδικού συστήματος ζύμης (Yeast two-hybrid), όπου χρησιμοποιήθηκε τμήμα του μορίου της δεσμίνης (το αμινο-τελικό άκρο), με το οποίο ‘σαρώθηκε’ (screening) μια cDNA καρδιακή βιβλιοθήκη, και βρέθηκε ένας αριθμός δυνητικών αλληλεπιδράσεων. Η σάρωση αποκάλυψε την αλληλεπίδραση της δεσμίνης με ένα νέο μόριο, τη Myospryn, μια μυοειδική πρωτεΐνη 413 kDa, μέλος της οικογένειας των TRIM-like πρωτεϊνών. Η πρωτεΐνη myospryn βρέθηκε αρχικά να αλληλεπιδρά με την πρωτεΐνη dysbindin, η οποία εμπλέκεται σε διαδικασίες διαμετακίνησης πρωτεϊνών, κυστιδίων και βιοσύνθεσης οργανιδίων, και αποτελεί συστατικό ενός πρωτεϊνικού συμπλόκου υπεύθυνου για τη βιογένεση λυσοσωμάτων και λυσοσωματικά συσχετιζόμενων οργανιδίων, γνωστό ως Biogenesis of Lysosome Related Organelles (BLOC-1). Η πρόσδεση της δεσμίνης με τη myospryn επαληθεύτηκε με in vitro μεθόδους (GST pull down assay, Co-immunoprecipitation). H ανάλυση ανοσοαποτύπωσης (western blot) απεκάλυψε ότι το ανοσολογικό σύμπλοκο που κατακρημνίζεται με χρήση αντισωμάτων δεσμίνης περιέχει, εκτός της myospryn, και δυο τουλάχιστον υπομονάδες του πρωτεϊνικού συμπλόκου BLOC-1, dysbindin και pallidin. Πειράματα με το δι-υβριδικό σύστημα ζύμης απεκάλυψαν την ακριβή περιοχή αλληλεπίδρασης των δύο πρωτεϊνών, και η οποία περιλαμβάνει τα αα58-103 του αμινο-τελικού άκρου της δεσμίνης και τα τελευταία 24αα του καρβόξυ-τελικού άκρου του μορίου της myospryn, που αντιστοιχούν στο SPRY τμήμα του TRIM-like μοτίβου της οικογένειας των πρωτεϊνών στην οποία ανήκει η myospryn. Πειράματα ανοσοφθορισμού σε απομονωμένα καρδιομυοκύτταρα απεκάλυψαν ότι η myospryn τοπολογείται στην περιφέρεια του πυρήνα, σε στενή γειτνίαση με τις μεμβράνες του ενδοπλασματικού δικτύου, και στο σημείο αυτό αλληλο-επικαλύπτεται με τη δεσμίνη, η οποία σχηματίζει ένα δίκτυο ινιδίων που διατρέχει όλο το μήκος του κυττάρου. Στον ενήλικο καρδιακό ιστό, η myospryn βρίσκεται κυρίως στους εμβόλιμους δίσκους, καθώς και στο επίπεδο της πλασματικής μεμβράνης, του σαρκολείματος, όπου και αλληλοεπικαλύπτεται με τη δεσμίνη. Η αλληλο-επικάλυψη των δυο πρωτεϊνών είναι έντονη στο επίπεδο των εμβόλιμων δίσκων. Δείχθηκε πως η myospryn άλληλο-επικαλύπτεται με τα λυσοσώματα καθώς και ότι η δεσμίνη είναι απαραίτητη τόσο για τη σωστή τοπολόγηση της myospryn, όσο και για αυτήν των λυσοσωμάτων. Τέλος, με πειράματα καταστολής τηw έκφρασης της myospryn, αποκαλύφθηκε πως η παρουσία της myospryn είναι απαραίτητη προκειμένου η δεσμίνη να μπορεί να ανοσοκατακρημνίσει τις υπομονάδες του BLOC-1, dysbindin και pallidin Τέλος, στην προσπάθεια χαρακτηρισμού του λειτουργικού ρόλου της myospryn συμπεριλήφθηκε η χρησιμοποίηση του μοντέλου του D. rerio (zebrafish). Χρησιμοποιώντας την τεχνολογία των antisense morpholinos, ήταν δυνατή η παρεμπόδιση της έκφρασης της myospryn και η μελέτη των επιπτώσεων στην ανάπτυξη και λειτουργία του καρδιακού ιστού. Η καταστολή της έκφρασης της myospryn είχε ως αποτέλεσμα σοβαρές δομικές και λειτουργικές ανωμαλίες στο καρδιακό σύστημα ατόμων Danio rerio, καταδεικνύοντας την σπουδαιότητα αυτού του μορίου στην ανάπτυξη του καρδιακού συστήματος του D.rerio. Συμπερασματικά η παρούσα διδακτορική διατριβή διαπραγματεύεται τις πρωτεϊνικές αλληλεπιδράσεις της μυοειδικής πρωτεΐνης δεσμίνης, αποκαλύπτοντας νέους ρυθμιστικούς ρόλους για το μόριο αυτό. / The scientific interest of this PhD thesis is mainly the role of desmin cytoskeleton (the muscle-specific intermediate filament) in myocyte maintenance and function. The ablation of desmin expression in mice by gene targeting demonstrated that desmin expression is crucial for maintanance of healthy muscle. Mice null for desmin develop dilated cardiomyopathy characterized by mitochondrial abnormalities, extensive cardiomyocyte death, fibrosis, calcification and eventually heart failure. Study of desmin protein interactions could facilitate our understanding of the molecular mechanisms responsible for the observed pathology. To that end, we have performed a yeast two-hybrid screening of a cardiac cDNA library We showed that the desmin amino-terminal domain [Naa(1 -103)] binds to a 413kDa TRIM-like protein, myospryn, originally identified as the muscle-specific partner of dysbindin, a component of the Biogenesis of Lysosome Related Organelles Complex 1 (BLOC-1). Binding of desmin with myospryn was confirmed with GST pull down assays and co-immunoprecipitation experiments. Western blot analysis revealed that the complex immunoprecipitated by desmin antibodies, in addition to myospryn contained the BLOC-1 components dysbindin and pallidin. Deletion analysis revealed that only the [Naa(1 -103)] fragment of desmin binds to myospryn carboxyl terminus and that this association takes place through the 24aa long C-terminal end of the SPRY domain of myospryn. Using an antibody against the COOH terminus of myospryn, we demonstrated that myospryn co-localizes with desmin at the periphery of the nucleus, in close proximity to the endoplasmic reticulum, of mouse neonatal cardiomyocytes. In adult heart muscle, the two proteins co localize, predominantly, at intercalated discs and costameres. We also showed that myospryn colocalizes with lysosomes. Using desmin null hearts, we demonstrated that desmin is required for both the proper perinuclear localization of myospryn, as well as the proper positioning of lysosomes, thus suggesting a potential role of desmin IFs in lysosomes and lysosome-related organelle biogenesis and/or positioning. siRNAs experiments for myospryn knock down revealed that when myospryn is absent, desmin is not able to immunoprecipitate BLOC-1 subunits. Additionally, the in vivo role of myospryn was examined using the model of D. rerio. Using a splice morpholino for knocking down myospryn transcript, we examined the effects on zebrafish heart development and function caused by the absence of myospryn, where it was shown that myospryn is essential for the early heart development in D.rerio. In summary, this work reveals the association of desmin with a novel molecule, myospryn, and it sheds light on novel regulatory role for this member of intermediate filament family.

Carnation Italian ringspot virus (CIRV) is a positive-strand RNA virus that assembles its membrane-bound replication complexes at mitochondria in plant cells. This process is accompanied by extensive inward invagination of the mitochondrial outer membrane, leading to the formation of cytosol-filled spherules, wherein viral RNA synthesis occurs. The mechanism by which CIRV is able to induce spherule formation is unknown, however growing evidence suggests that the host-cell ESCRT (Endosomal Sorting Complex Required for Transport) machinery – a multi-protein complex normally involved in late endosome maturation – may be involved. ESCRT consists of ~30 soluble proteins that form sub-complexes assembled at the late endosomal surface, and function in multivesicular body (MVB) biogenesis. While ESCRT is relatively well characterized in yeasts and mammals, comparably little is known about ESCRT in plants. Hence, as an initial step towards understanding the potential role of ESCRT in CIRV replication, we examined the protein-protein interaction network, subcellular localization, and gene expression profiles of the Arabidopsis thaliana ESCRT components. Overall, the results from these studies suggest that ESCRT organization and function is relatively well conserved in plants compared to other eukaryotes. We also observed that ESCRT is important for CIRV replication, as expression of dominant-negative versions of several key ESCRT components reduced CIRV replication efficiency in plant cells. Moreover, the Arabidopsis ESCRT-I component, Vps23A is recruited from late endosomes to mitochondria in plant cells expressing the CIRV replicase protein, p36, and recruitment of Vps23A was shown to be mediated by sequences located at the N terminus of p36. It was also shown that recruitment of Vp23A to mitochondria by p36 does not require the Ubiquitin E2 Variant domain of Vps23A, which is in contrast to recruitment of ESCRT by retroviruses during viral budding in mammalian cells. Taken together, these results support the hypothesis that CIRV recruits ESCRT by a novel mechanism in order to carry out its replication, a finding that may lend important insight to aspects of normal ESCRT function in plants.

Protein disulfide isomerases (PDIs) catalyze the oxidation and isomerization of disulfide bonds in proteins passing through the endoplasmic reticulum (ER). Although as many as 20 enzymes are classified as PDI family members, their relative contributions to protein folding have remained an open question. Additionally, Ero1 has been characterized as the ER oxidase that transfers oxidizing equivalents from oxygen to PDI enzymes. However, knockout mice lacking the mammalian Ero1 isoforms, Ero1Lα and Ero1Lβ, are viable, and the role of other potential ER oxidases in maintaining an oxidative ER environment is now an important issue. By systematic depletion of ER PDI family members and potential ER oxidases and assessment of disulfide bond formation of secreted endogenous substrates, I have outlined the functional relationships among some of these enzymes. PDI family member depletion revealed that PDI, although not essential for complete disulfide bond formation in client proteins, is the most significant catalyst of oxidative folding. In comparison, ERp57 acts preferentially on glycosylated substrates, ERp72 functions in a more supplementary capacity, and P5 has no detectable role in formation of disulfide bonds for the substrates assayed. Initially, no impact of depletion of Ero1 was observed under steady state conditions, suggesting that other oxidase systems are working in parallel to support normal disulfide bond formation. Subsequent experiments incorporating a reductive challenge revealed that Ero1 depletion produces the strongest delay in re-oxidation of the ER and oxidation of substrate. Depletion of two other potential ER oxidases, peroxiredoxin 4 (PRDX4) and Vitamin K epoxide reductase (VKOR), showed more modest effects. Upon co-depletion of Ero1 and other oxidases, additive effects were observed, culminating in cell death following combined removal of Ero1, PRDX4, and VKOR activities. These studies affirm the predominant roles of Ero1 in ER oxidation processes and, for the first time, establish VKOR as a significant contributor to disulfide bond formation.

No description available.

Les cellules souches (CS) se démarquent des progéniteurs et cellules différenciées à de nombreux égards. Notamment, les CS présentent des caractéristiques particulières dans des processus cellulaires fondamentaux, et il a été récemment proposé que la biogenèse des ribosomes (BiRi) participe à la régulation des CS. Pendant ma thèse, j’ai utilisé diverses approches pour étudier le rôle et la régulation de la BiRi dans des populations de CS, in vivo et ex vivo dans des modèles murins.Grâce à un modèle d’inactivation génétique du facteur de BiRi Notchless (Nle), j’ai participé à l’étude de son rôle dans le lignage hématopoïétique et l’épithélium intestinal adultes, et cours du développement embryonnaire précoce. In vivo, la perte constitutive de Nle entraîne une létalité embryonnaire, et j’ai montré ex vivo que l’inactivation de Nle dans des CS embryonnaires induit une réponse au stress ribosomique médiée par le suppresseur de tumeur p53, et des défauts de prolifération/survie. L’induction de la perte de Nle chez l’adulte active également p53 dans les CS hématopoïétiques et intestinale, entraînant leur rapide élimination.En parallèle, j’ai utilisé plusieurs méthodes pour mesurer l’activité de BiRi des progéniteurs immatures et CS hématopoïétiques (CSH) à l’homéostasie, in vivo chez la souris adulte. J’ai ainsi mis en évidence des variations de l’activité de BiRi dans ces populations, révélant notamment une activité de BiRi des CSH jusqu’ici insoupçonnée du fait de leur quiescence.Dans l’ensemble, mon travail renforce l’idée d’un rôle de la BiRi dans la régulation des CS, et apporte une meilleure compréhension de la régulation de ce processus dans le lignage hématopoïétique. / Stem cells (SCs) differ from progenitors and differentiated cells on many aspects. Notably, SCs display particular characteristics in fundamental cellular processes, and ribosome biogenesis (RiBi) has recently been proposed to play an important role in the regulation of SCs. During my thesis, I have used various approaches to study the role and regulation of RiBi in SC populations, using in vivo and ex vivo mouse models.Using genetic inactivation of the RiBi factor Notchless (Nle), I have participated to the analysis of its role in the adult hematopoietic system and intestinal epithelium, and in the establishment of the first cell lineages during early embryogenesis. In vivo, constitutive Nle deficiency causes early embryonic lethality, and I showed ex vivo that Nle inactivation in embryonic SCs induces a ribosomal stress response mediated by the tumor suppressor p53, and proliferation/survival defects. Conditional Nle inactivation in the adult mouse also induces activation of p53 in hematopoietic and intestinal SCs in vivo, leading to their rapid elimination.In parallel, I have used different methods to analyze the RiBi activity of hematopoietic SCs (HSCs) and immature progenitors at homeostasis, in vivo in the adult mouse. Thus, I have unraveled variations in the RiBi activity of these populations, and notably uncovered previously unsuspected RiBi activity in HSCs despite their quiescent state.Altogether, my work supports the hypothesis of a role for RiBi in the regulation of SCs and provides better understanding of the activity of this process during hematopoietic differentiation.

Dans un premier temps, je me suis intéressé à la sous-unité ε de l’ATP synthase mitochondriale chez la levure, un organisme qui se prête bien à l’étude des fonctions mitochondriales. Cette protéine fait partie d’un élément de l’ATP synthase appelé la tige centrale. Celui-ci permet de coupler le domaine translocateur de protons de cette enzyme (FO) à son secteur catalytique (F1) où l’ATP est synthétisé. En utilisant un système d’expression régulable (répressible par la doxycycline), j’ai montré qu’en l’absence de la sous-unité ε les secteurs F1 et FO ne sont plus couplés, avec pour résultat des fuites massives de protons à travers la membrane interne des mitochondries. J’ai ensuite montré que l’absence de la sous-unité ε peut être compensée par des mutations ralentissant l’activité du FO. Ces données permettent de conclure que la sous-unité ε est nécessaire au maintien de l’intégrité physique de l’ATP synthase lors de son fonctionnement. Dans un second temps, j’ai cherché à identifier de nouveaux facteurs intervenant dans la biogenèse du FO. Pour cela, j’ai utilisé un crible génétique où la survie des cellules de levure est conditionnée à des mutations inactivation le FO. Un millier d’isolats a été analysé. Les mutations ont été localisées dans les génomes mitochondrial et nucléaire. Dix-huit clones, issus de mutations n’affectant pas des facteurs connus pour être nécessaires à l’expression de l’ATP synthase, ont été entièrement séquencés. Plusieurs nouveaux systèmes cellulaires potentiellement impliqués dans la biogenèse du FO ont été identifiés. / At first, I am interested in the ε subunit of mitochondrial ATP synthase in yeast, an organism that is well suited for the study of mitochondrial functions. This protein is a part of the ATP synthase called central stalk. This allows the coupling of proton translocator domain of this enzyme (FO) to its catalytic domain (F1) where ATP is synthesized. Using a tetO expression system, I showed that in the absence of the ε subunit, F1 and FO domains are no longer coupled. It results in a massive proton leakage across the inner membrane of mitochondria. I then showed that the absence of the ε subunit can be compensated by mutations slowing the activity of FO. These data allow to conclude that the ε subunit is necessary to maintain the physical integrity of the ATP synthase for oxydative phosphorylation. Later, I tried to identify new factors involved in the biogenesis of the FO. For this, I used a genetic screen where the survival of yeast cells is conditioned by mutations inactivating the FO. About a thousand clones were analyzed. The mutations were localized in mitochondrial and nuclear genomes. Eighteen clones with mutations in genes encoding not yet known ATP synthase expression factors were completely sequenced. Several new cellular systems that are potentially involved in the biogenesis of FO were identified.

This thesis focuses on iron sulfur (Fe-S) cluster biogenesis by the ISC machinery in the mitochondrion of Trypanosoma brucei. Most of proteins in the pathway show conserved functions, while some features are distinct from their counterparts in other organisms. We also show here the essentiality of the ISC machinery in bloodstream stage despite the fact that the parasites contain the rudimentary mitochondrion in this stage. The key player for the ISC export machinery, which is indispensable in the maturation of extra-mitochondrial Fe-S proteins, shows some extraordinary phenomena which may imply the moonlighting function of the protein. I also show preliminary data of an ongoing project concerning a putative heme transporter. The results indicate role in heme uptake of the protein, but further study is required to confirm the function of the protein.

The mammalian mitochondria contain their own genome which encodes thirteen polypeptide components of the oxidative phosphorylation (OxPhos) system, and the mitochondrial (mt-) rRNAs and tRNAs required for their translation. The maturation of the mitochondrial ribosome requires both mt-rRNAs to undergo post-transcriptional chemical modifications, folding of the rRNA and assembly of the protein components assisted by numerous biogenesis factors. The post-transcriptional modifications of the mt-rRNAs include base methylations, 2’-O-ribose methylations and pseudouridylation. However, the exact function of these modifications is unknown. Many mitoribosome biogenesis factors still remain to be identified and characterised. This work aims to broaden our understanding of two proteins involved in mitoribosome biogenesis through the study of the function of an rRNA methyltransferase and a novel biogenesis factor. Firstly, we characterised MRM1 (mitochondrial rRNA methyltransferase 1), a highly conserved 2’-O-ribose methyltransferase. We confirmed that MRM1 modifies a guanine in the peptidyl (P) transferase region of the 16S mt-rRNA that specifically interacts with the 3’ end of the tRNA at the ribosomal P-site. In bacteria, the modification is dispensable for ribosomal biogenesis and cell viability under standard conditions. However, in yeast mitochondria, Mrm1p is vital for ribosomal assembly and function. We generated knockout cells lines using programmable nuclease technology, and characterised the possible effects of MRM1 depletion on mitochondrial translation and mitoribosome biogenesis. We demonstrated that neither the enzyme nor the modification is required for human mitoribosomal assembly and translation in our experimental setup. Secondly, we identified a novel mitochondrially-targeted putative RNA endonuclease, YbeY. Using YbeY knockout cell lines, we showed that depletion of YbeY leads to loss of cell viability and OxPhos function as a consequence of a severe decrease in mitochondrial translation. Northern blotting and transcriptomic analysis using next generation RNA-Seq revealed transcript-specific changes to steady state levels. This analysis identified mt-tRNASer as a potential target of YbeY. We investigated the effect of YbeY deficiency on mitoribosomal assembly by quantitative sucrose gradient fractionation and mass spectrometry. This analysis showed that the mt-SSU is depleted in YbeY knockout cells. Further, immunoaffinity purification identified MRPS11 as a key interactor of YbeY. We propose that YbeY is a multifunctional protein that performs endonucleolytic functions in the mitochondria and also acts as a mitochondrial ribosome biogenesis factor, assisting small subunit assembly through its interaction with MRPS11.

O tema desta pesquisa é a influência da atividade de minhocas no solo de uma vertente do Planalto Atlântico Paulista. O local estudado está cercado por áreas de preservação ambiental, possui florestas primárias em bom estado de conservação e apresenta clima quente com precipitações acima dos 2.000 mm por ano. Foi feito um levantamento das comunidades de anelídeos a partir de três diferentes técnicas de extração. Os organismos coletados foram identificados em nível de espécie e sua distribuição foi analisada ao longo da topografia. Demonstrou-se uma variação das populações de minhocas nos três setores da vertente, com maiores densidades no sopé e menores no topo. Verificou-se que há uma intensa atividade desses organismos no solo e que eles não se distribuem igualmente no perfil vertical, concentrando-se em algumas camadas, às vezes superficiais às vezes subsuperficiais, de acordo com o tipo de solo. Observou-se também a presença de espécies exóticas nas áreas antrópicas. Foi constatado que a atividade desses organismos modifica a morfologia (bioagregação) e também os atributos físicos (macroporosidade; bioporos) e químicos do solo (teores de matéria orgânica e dos nutrientes P, K+, Ca2+ e Mg2+; soma de bases; capacidade de troca catiônica), influenciando diversos processos pedológicos. Com seus comportamentos ecológicos (alimentar e construtor), as minhocas criam galerias, canais e produzem dejeções, ajudando na aeração do solo, na dinâmica hídrica e no processo de ciclagem dos nutrientes. Apesar do papel que desempenham na formação da cobertura pedológica, a maior parte dos levantamentos de solo não contempla os agregados biogênicos, por este motivo, demos ênfase especial à descrição destas morfologias. / The focus of this research is the activity of earthworms and their influence on the soil of an Atlantic Plateau hill slope in São Paulo State. Our area of study is surrounded by environmental preservation areas, it has primary forests in good conditions, warm climate and precipitations above 2,000 mm per year. Three different extraction techniques were used for the survey of annelid communities. The collected organisms were identified at the species level and its distribution was analyzed along the topography. We found a variation of earthworm populations in the three sectors of the slope, with the highest densities in the foothills and lower densities in the top. There is an intense activity of these organisms in the soil and they are not equally distributed in the vertical profile, concentrating on a few layers, sometimes in topsoil, sometimes in subsoil. We also observed the presence of exotic species in disturbed areas. The activity of soil fauna changes the morphology (bioaggregation), the physical (macroporosity), and chemical (P, K+, Ca2+, Mg2+ and organic matter dynamics, sum of bases and cation exchange capacity) attributes of soil, affecting many pedological processes. With their feeding and builder ecological behaviors, earthworms create galleries, channels and produce casts, helping in soil aeration, the water dynamics and nutrient cycling processes. Despite the role they play in the formation of soil mantle, most of the ground surveys does not include the biogenic aggregates, therefore, we gave special emphasis on the descriptions of such morphologies.