scholarly journals Λειτουργική ανάλυση του γονιδίου Snipper στη Drosophila melanogaster

2016 ◽  
Author(s):  
Αναστάσιος Αλεξιάδης
Keyword(s):  
Drosophila Melanogaster ◽  
Schizosaccharomyces Pombe ◽  
Mus Musculus ◽  
Homo Sapiens ◽  
5.8S Rrna

Η RNA εξωνουκλεάση ERI-1 (Enhanced RNAi-1) εντοπίστηκε σε μια γενετική σάρωση στο Ceanorabditis elegans σαν αρνητικός ρυθμιστής της RNA παρεμβολής (RNAi). Ο μηχανισμός δράσης που προτάθηκε είναι η αποκοπή των δυο προεξεχόντων νουκλεοτιδίων από τα μικρά παρεμβαλλόμενα RNA (siRNA) γεγονός που τα καθιστά ανενεργά. Το ομόλογό της στον Homo sapiens και στον Mus musculus αλληλεπιδρά με το 3 ́άκρο των ιστονικών μεταγράφων απομακρύνοντας τα τελευταία νουκλεοτίδια τους και συμμετέχοντας στη ρύθμιση της αποικοδόμησης τους στο τέλος της S φάσης. Επιπλέον η ERI-1 στο Schizosaccharomyces pombe, το Ceanorabditis elegans και το Mus musculus συμμετέχει στην ωρίμανση του 5.8S rRNA αποκόπτοντας δυο νουκλεοτίδια από το 3 ́άκρο του. Φαίνεται λοιπόν ότι πρόκειται για μια σημαντική εξωνουκλεάση που παρεμβαίνει σε κεντρικούς κυτταρικούς μηχανισμούς που μεσολαβούνται από μόρια RNA. Για τον λόγο αυτό επιλέξαμε να μελετήσουμε τη δράση της στη Drosophila melanogaster όπου οι γνώσεις μας περιοριζόταν στον βιοχημικό χαρακτηρισμό του εκεί ομολόγου Snipper (Snp) σαν εξωνουκλεάση. Η μελέτη βασίστηκε σε μεταλλάγματα ένθεσης και υποέκφρασης του Snp μέσω RNA παρεμβολής, καθώς και σε διαγονιδιακές σειρές που το υπερεκφράζουν ώστε να διερευνηθεί η πιθανή εμπλοκή του σε κάποιο από τα γνωστά μονοπάτια. Τα αποτελέσματά μας έδειξαν ότι το Snp είναι ένα απαραίτητο γονίδιο για την ανάπτυξη της Drosophila melanogaster. Τα μετάγραφα του παρέχονται στο έμβρυο από την μητέρα και η μείωση της έκφρασης του οδηγεί σε αναστολή της ανάπτυξης σε συγκεκριμένα στάδια. Επιπλέον η υποέκφραση του σε διάφορους ιστούς προκαλεί παραμορφώσεις και αποκλίσεις από τη φυσιολογική τους μορφολογία. Σε συμφωνία με την αποκλίνουσα βιογένεση του 5.8S rRNA στη δροσόφιλα η απουσία του Snp δε φαίνεται να το επηρεάζει. Αντίθετα στην περίπτωση των μεταγράφων των ιστονικών RNA η απουσία του Snp οδηγεί σε ανάλογη μείωση των επιπέδων τους. Το φαινόμενο αυτό οφείλεται σε άμεση επίδραση της πρωτεΐνης Snp επί των ιστονικών mRNA όπως δείξαμε με πειράματα ανοσοκατακρήμνισης. Επιπλέον η αλληλούχιση των 3 ́άκρων των μεταγράφων της ιστόνης 3 έδειξε ότι η επεξεργασία τους απουσία της Snp είναι προβληματική, καθώς δεν αποκόπτονται τα δύο τελικά νουκλεοτίδια. Η υπόθεση πουΑΝΑΣΤΑΣΙΟΣ ΑΛΕΞΙΑΔΗΣ1προτείνεται είναι ότι η Snp συμμετέχει στην ωρίμανση ή/και στην προστασία του 3 ́άκρου των ιστονών. Η απουσία της οδηγεί σε μειωμένη αφθονία των ιστονικών μεταγράφων πιθανότατα λόγω αυξημένης αποικοδόμησης. Αυτό με τη σειρά του καθυστερεί ή αναστέλλει την ολοκλήρωση του κυτταρικού κύκλου.

Promoter Structures Conserved between Homo Sapiens, Mus Musculus and Drosophila Melanogaster

2013 ◽  
pp. 1522-1534
Author(s):  
Boris R. Jankovic ◽  
John A. C. Archer ◽  
Rajesh Chowdhary ◽  
Ulf Schaefer ◽  
Vladimir B. Bajic
Keyword(s):  
Drosophila Melanogaster ◽  
Mus Musculus ◽  
Transcription Initiation ◽  
Homo Sapiens ◽  
Great Part ◽  
Sequence Motifs ◽  
Regulatory Structure ◽  
Promoter Regions ◽  
Promoter Architecture ◽  
Living Organisms

Some of the key processes in living organisms remain essentially unchanged even in evolutionarily very distant species. Transcriptional regulation is one such fundamental process that is essential for cell survival. Transcriptional control exerts great part of its effects at the level of transcription initiation mediated through protein-DNA interactions mainly at promoters but also at other control regions. In this chapter, the authors identify conserved families of motifs of promoter regulatory structures between Homo sapiens, Mus musculus and Drosophila melanogaster. By a promoter regulatory structure they consider here a combination of motifs from identified motif families. Conservation of promoter structure across these vertebrate and invertebrate genomes suggests the presence of a fundamental promoter architecture and provides the basis for deeper understanding of the necessary components of the transcription regulation machinery. The authors reveal the existence of families of DNA sequence motifs that are shared across all three species in upstream promoter regions. They further analyze the relevance of our findings for better understanding of preserved regulatory mechanisms and associated biology insights.

Promoter Structures Conserved between Homo Sapiens, Mus Musculus and Drosophila Melanogaster

2011 ◽  
pp. 92-104
Author(s):  
Boris R. Jankovic ◽  
John A. C. Archer ◽  
Rajesh Chowdhary ◽  
Ulf Schaefer ◽  
Vladimir B. Bajic
Keyword(s):  
Drosophila Melanogaster ◽  
Mus Musculus ◽  
Transcription Initiation ◽  
Homo Sapiens ◽  
Great Part ◽  
Sequence Motifs ◽  
Regulatory Structure ◽  
Promoter Regions ◽  
Promoter Architecture ◽  
Living Organisms

Some of the key processes in living organisms remain essentially unchanged even in evolutionarily very distant species. Transcriptional regulation is one such fundamental process that is essential for cell survival. Transcriptional control exerts great part of its effects at the level of transcription initiation mediated through protein-DNA interactions mainly at promoters but also at other control regions. In this chapter, the authors identify conserved families of motifs of promoter regulatory structures between Homo sapiens, Mus musculus and Drosophila melanogaster. By a promoter regulatory structure they consider here a combination of motifs from identified motif families. Conservation of promoter structure across these vertebrate and invertebrate genomes suggests the presence of a fundamental promoter architecture and provides the basis for deeper understanding of the necessary components of the transcription regulation machinery. The authors reveal the existence of families of DNA sequence motifs that are shared across all three species in upstream promoter regions. They further analyze the relevance of our findings for better understanding of preserved regulatory mechanisms and associated biology insights.

scholarly journals Comprehensive Overview and Assessment of microRNA Target Prediction Tools in Homo sapiens and Drosophila melanogaster

2019 ◽  
Vol 14 (5) ◽  
pp. 432-445 ◽  
Author(s):  
Muniba Faiza ◽  
Khushnuma Tanveer ◽  
Saman Fatihi ◽  
Yonghua Wang ◽  
Khalid Raza
Keyword(s):  
Drosophila Melanogaster ◽  
Mirna Target ◽  
Homo Sapiens ◽  
Target Prediction ◽  
Computational Prediction ◽  
Transcriptional Level ◽  
Mirna Target Prediction ◽  
Microrna Target ◽  
Prediction Tools ◽  
Mirna Targets

Background: MicroRNAs (miRNAs) are small non-coding RNAs that control gene expression at the post-transcriptional level through complementary base pairing with the target mRNA, leading to mRNA degradation and blocking translation process. Many dysfunctions of these small regulatory molecules have been linked to the development and progression of several diseases. Therefore, it is necessary to reliably predict potential miRNA targets. Objective: A large number of computational prediction tools have been developed which provide a faster way to find putative miRNA targets, but at the same time, their results are often inconsistent. Hence, finding a reliable, functional miRNA target is still a challenging task. Also, each tool is equipped with different algorithms, and it is difficult for the biologists to know which tool is the best choice for their study. Methods: We analyzed eleven miRNA target predictors on Drosophila melanogaster and Homo sapiens by applying significant empirical methods to evaluate and assess their accuracy and performance using experimentally validated high confident mature miRNAs and their targets. In addition, this paper also describes miRNA target prediction algorithms, and discusses common features of frequently used target prediction tools. Results: The results show that MicroT, microRNA and CoMir are the best performing tool on Drosopihla melanogaster; while TargetScan and miRmap perform well for Homo sapiens. The predicted results of each tool were combined in order to improve the performance in both the datasets, but any significant improvement is not observed in terms of true positives. Conclusion: The currently available miRNA target prediction tools greatly suffer from a large number of false positives. Therefore, computational prediction of significant targets with high statistical confidence is still an open challenge.

Transformation of Drosophila melanogaster with a suppressor tRNA gene from Schizosaccharomyces pombe

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 211-217 ◽  
Author(s):  
Charles M. Molnar ◽  
Tove Reece ◽  
James A. Williams ◽  
John B. Bell
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
In Situ Hybridization ◽  
Schizosaccharomyces Pombe ◽  
Southern Hybridization ◽  
Trna Gene ◽  
P Element ◽  
Suppressor Trna ◽  
Good Agreement

P-element mediated transformation was utilized to introduce a suppressor tRNA gene [Formula: see text] from Schizosaccharomyces pombe into Drosophila melanogaster. Thirteen independently transformed lines were characterized as to the number and cytological locations of the transposons. It was ascertained that the suppressor tRNA gene of interest was introduced into each transformed strain. The helper P element used (pπ25.1) allows further transposition to occur, and it was determined that from one to seven copies of the heterologous [Formula: see text] gene per strain were present among the respective transformed strains. The number of transposons per transformed line was established by in situ hybridization to salivary gland chromosomes as well as by Southern hybridization analyses and there was good agreement in the totals determined by these two techniques.Key words: Drosophila, Schizosaccharomyces, tRNA suppressor, transformation, transposon.

scholarly journals Similar Efficacies of Selection Shape Mitochondrial and Nuclear Genes in Both Drosophila melanogaster and Homo sapiens

2015 ◽  
Vol 5 (10) ◽  
pp. 2165-2176 ◽  
Author(s):  
Brandon S. Cooper ◽  
Chad R. Burrus ◽  
Chao Ji ◽  
Matthew W. Hahn ◽  
Kristi L. Montooth
Keyword(s):  
Drosophila Melanogaster ◽  
Homo Sapiens ◽  
Nuclear Genes

Implication of Nanoparticles in Drosophila Toxicology Research

2021 ◽  
pp. 330-340
Author(s):  
Sumira Malik
Keyword(s):  
Drosophila Melanogaster ◽  
Development Process ◽  
Homo Sapiens ◽  
Model Organism ◽  
Fruit Fly ◽  
Biological Species ◽  
Biological Pathways ◽  
Nano Particles ◽  
Genetic Homology

Homo sapiens and Drosophila malenogaster, a fruit fly, share genetic homology in development process regulated through fundamental biological pathways and conserved mechanisms conserved as a process of evolution among these species. Drosophila melanogaster is an eminent model organism to study diverse biological species. In this chapter, the use of wide variety of nano particles and their impact on Drosophila melanogastsr's development, longevity, characteristics of reproduction has been studied.

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