Biomedical subjects

Ilenia D'Errico

Publications and source records attributed to Ilenia D'Errico.

4 recordsLinked to original sources

PubMed2005

History of the Tfam gene in primates.

Tfam is a single copy nuclear gene mapping on chromosome 10 in human and mouse, 20 in rat and 12 in Presbytis cristata. It encodes for an HMG (high-mobility-group) protein showing a high affinity with the two transcriptional promoters and other mitochondrial DNA regions. It is an activator of mitochondrial transcription acting in the presence of mitochondrial RNA polymerase and of transcription factor B. Other interesting features of Tfam gene in human and rat are reported such as the existence of a smaller isoform, originated by an alternative splicing mechanism of the exon 5 (delta5 isoform) and the presence of different processed pseudogenes in addition to the active copy of the gene. In order to widen knowledge about Tfam gene and the appearance of some of its properties in the evolutionary history of primates, we have studied some aspects of this gene in different species. In particular we have determined its chromosomal localization, suggesting that its locus is highly conserved; we have searched for the presence of the delta5 isoform, demonstrating that it is present only in hominids; we have provided evidence of Tfam processed pseudogenes in the majority of the analysed genomes. Sequence data from this article have been deposited in the EMBL nucleotide database.

Animals↗

PubMed2004

Pseudogenes in metazoa: origin and features.

The complete genome sequences with their annotations are a considerable resource in biology, particularly in understanding the global structure of the genetic material at the molecular level. The reason why some eukaryotic genomes contain large quantities of apparently unnecessary DNA, namely pseudogenes, while others seem to invest in more efficient thinning processes or are equipped with protection systems against parasitic elements still remains a mystery. Several genome-wide surveys have been undertaken to identify pseudogenes in the completely sequenced genome, bringing to light some differences both in their amount and distribution. Since pseudogenes are important resources in evolutionary and comparative genomics - as 'molecular fossils' - in this paper, a survey on the origins, features, abundance and localisation of the different pseudogenes is reported. As an example of genes producing processed pseudogenes, some experimental data obtained in the authors' laboratories from the study of a nuclear gene coding for the mitochondrial transcription factor A (mtTFA), a key regulator of mitochondrial biogenesis, are also reported.

Animals↗

PubMed2002

Molecular strategies in Metazoan genomic evolution.

During the evolution of Metazoa, the mitochondrial genome has remained practically unchanged as indicated by its small size and constant gene content in each lineage, although several evolutionary processes have taken place. In contrast, the nuclear genome of Metazoa has undergone dramatic changes, as is demonstrated by some entire genomes completely sequenced so far. The expansion of gene families and the appearance of new functions and new regulatory circuits are among the most prominent features. Here, we report a description of the evolution of the p53 gene family as an example of expansion of both genetic complexity and gene expression of the nuclear genome.

Alternative Splicing↗

PubMed2002

Characterization of the mtTFA gene and identification of a processed pseudogene in rat.

Mitochondrial DNA replication and transcription are regulated from essential nucleus-encoded components that interact with the mitochondrial (mt) D-loop region. Among these there is the mitochondrial transcription factor A (mtTFA or Tfam). We have determined the sequence of the cDNA mtTFA in rat and have demonstrated that the gene has a mosaic organization with six introns whose sizes we have calculated. A differential splicing transcript lacking exon 5 has been detected in all assayed tissues and represents 9.85% of the full length transcript. Beside the gene which is homologous to the one found in man and mouse, rat nuclear genome contains at least 12 copies of this gene or genome fragments with high similarity to mtTFA. We have determined the sequence of one of these copies. This resulted to have 76.26% similarity to the active gene but to lack introns, suggesting it might be a processed pseudogene. RT-PCR experiments have demonstrated that this pseudogene (psi mtTFA) is transcribed in liver tissue.

Alternative Splicing↗