Biomedical subjects

Andrea Zuccolo

Publications and source records attributed to Andrea Zuccolo.

5 recordsLinked to original sources

PubMed2025

Transposable elements drive evolution and perturb gene expression in Brassica rapa and B. oleracea.

Transposable elements (TEs) significantly influence genomic diversity and gene regulation in plants. Brassica rapa and B. oleracea, with their distinct domestication histories, offer excellent models to explore TE dynamics. Here, we developed a refined TE classification method and systematically analyzed TEs across 12 B. rapa and B. oleracea genomes, identifying 1878 TE families. Approximately half (49.5%) of these TE families were shared between the two species, reflecting a common evolutionary origin, whereas species-specific expansions, particularly among long-terminal repeat (LTR) retrotransposons, underscore their roles in genomic differentiation. We notably characterized a heat-responsive Ty1-copia family (Copia0035) in B. oleracea roots, distinguished by low GC content and the absence of CG and CHG methylation motifs, sharing regulatory similarities with the Arabidopsis heat-induced ONSEN element. Syntenic analyses of gene-TE associations highlighted significant intraspecies TE insertion variability, with more accession-specific insertions in B. rapa and more conserved insertions, often associated with distinct morphotypes in B. oleracea. Gene ontology enrichment indicated TE involvement in developmental, reproductive, and stress response pathways. Transcriptome analysis across diverse accessions revealed that genes proximal to TEs, particularly those regulating floral development and flowering time, exhibit increased expression variability. These findings advance our understanding of TE-mediated genome evolution in Brassica species and underscore their potential utility in breeding and genome engineering strategies for crop improvement.

DNA Transposable Elements↗

PubMed2006

RetrOryza: a database of the rice LTR-retrotransposons.

Long terminal repeat (LTR)-retrotransposons comprise a significant portion of the rice genome. Their complete characterization is thus necessary if the sequenced genome is to be annotated correctly. In addition, because LTR-retrotransposons can influence the expression of neighboring genes, the complete identification of these elements in the rice genome is essential in order to study their putative functional interactions with the plant genes. The aims of the database are to (i) Assemble a comprehensive dataset of LTR-retrotransposons that includes not only abundant elements, but also low copy number elements. (ii) Provide an interface to efficiently access the resources stored in the database. This interface should also allow the community to annotate these elements. (iii) Provide a means for identifying LTR-retrotransposons inserted near genes. Here we present the results, where 242 complete LTR-retrotransposons have been structurally and functionally annotated. A web interface to the database has been made available (http://www.retroryza.org/), through which the user can annotate a sequence or search for LTR-retrotransposons in the neighborhood of a gene of interest.

Databases, Nucleic Acid↗

PubMed2006

Construction of a nurse shark (Ginglymostoma cirratum) bacterial artificial chromosome (BAC) library and a preliminary genome survey.

BACKGROUND: Sharks are members of the taxonomic class Chondrichthyes, the oldest living jawed vertebrates. Genomic studies of this group, in comparison to representative species in other vertebrate taxa, will allow us to theorize about the fundamental genetic, developmental, and functional characteristics in the common ancestor of all jawed vertebrates. AIMS: In order to obtain mapping and sequencing data for comparative genomics, we constructed a bacterial artificial chromosome (BAC) library for the nurse shark, Ginglymostoma cirratum. RESULTS: The BAC library consists of 313,344 clones with an average insert size of 144 kb, covering ~4.5 x 1010 bp and thus providing an 11-fold coverage of the haploid genome. BAC end sequence analyses revealed, in addition to LINEs and SINEs commonly found in other animal and plant genomes, two new groups of nurse shark-specific repetitive elements, NSRE1 and NSRE2 that seem to be major components of the nurse shark genome. Screening the library with single-copy or multi-copy gene probes showed 6-28 primary positive clones per probe of which 50-90% were true positives, demonstrating that the BAC library is representative of the different regions of the nurse shark genome. Furthermore, some BAC clones contained multiple genes, making physical mapping feasible. CONCLUSION: We have constructed a deep-coverage, high-quality, large insert, and publicly available BAC library for a cartilaginous fish. It will be very useful to the scientific community interested in shark genomic structure, comparative genomics, and functional studies. We found two new groups of repetitive elements specific to the nurse shark genome, which may contribute to the architecture and evolution of the nurse shark genome.

Animals↗

PubMed2005

Gene duplication and exon shuffling by helitron-like transposons generate intraspecies diversity in maize.

We report a whole-genome comparison of gene content in allelic BAC contigs from two maize inbred lines. Genic content polymorphisms involve as many as 10,000 sequences and are mainly generated by DNA insertions. The termini of eight of the nine genic insertions that we analyzed shared the structural hallmarks of helitron rolling-circle transposons. DNA segments defined by helitron termini contained multiple gene-derived fragments and had a structure typical of nonautonomous helitron-like transposons. Closely related insertions were found in multiple genomic locations. Some of these produced transcripts containing segments of different genes, supporting the idea that these transposition events have a role in exon shuffling and the evolution of new proteins. We identified putative autonomous helitron elements and found evidence for their transcription. Helitrons in maize seem to continually produce new nonautonomous elements responsible for the duplicative insertion of gene segments into new locations and for the unprecedented genic diversity. The maize genome is in constant flux, as transposable elements continue to change both the genic and nongenic fractions of the genome, profoundly affecting genetic diversity.

Base Sequence↗

PubMed2005

Structured motifs search.

In this paper, we describe an algorithm for the localization of structured models, i.e. sequences of (simple) motifs and distance constraints. It basically combines standard pattern matching procedures with a constraint satisfaction solver, and it has the ability, not present in similar tools, to search for partial matches. A significant feature of our approach, especially in terms of efficiency for the application context, is that the (potentially) exponentially many solutions to the considered problem are represented in compact form as a graph. Moreover, the time and space necessary to build the graph are linear in the number of occurrences of the component patterns.

Algorithms↗