LENGTH HETEROPLASMY IN THE PREDOMINATE MITOCHONDRIAL DNA HAPLOGROUPS IN THE CROATIAN POPULATION

Mitochondrial control region represents the most variable segment of the mitochondrial genome. The frequency and pattern of heteroplasmy has been described in several studies; however, none of the reports documented the Croatian population. In the present study, we screened the control region (1122 bp) of 95 individuals belonging to two predominant mitochondrial phylogenetic branches in the Croatian population, haplogroups H and U. Length heteroplasmy occurred in polycytosine (poly-C) tracts within three hypervariable segments of the control region with the following frequencies: HVSI - 26.3%, HVSII - 52.6% and HVSIII - 7.4%. Furthermore, the association between certain polymorphisms in HVSI and length heteroplasmy was investigated. Our results indicate that only polymorphisms located in the poly-C tract are associated with HVSI length heteroplasmy. The T to C transition at np 16189 is significantly associated with the occurrence of length heteroplasmy (p<0.0001). This effect was even stronger if the C insertion was present in the position 16193. The data support the hypothesis that an uninterrupted poly-C tract of more than eight cytosines leads to length heteroplasmy. Length heteroplasmy associated with the T to C substitution in np 16189 was predominantly found in haplogroup U

Response To Hyperoxia Is Associated With Similar Ho-1 Gene Expression Level In Lungs Of Aging Cba Mice Of Both Sexes

Beside classical antioxidative enzymes, the response to hyperoxia might be mediated via regulation of other systems, such as heme oxygenase (HO). Ho-1 gene expression is found to be upregulated by hyperoxia in all groups of mice, while HO-1 protein isoform was increased only in 4 months old male mice. In steady-state conditions ho-1 and ho-2 gene expression remained unchanged irrespective of sex or age, which was not the case with protein level of both isoforms. This study suggests that in lungs of CBA mice the response to oxidative stress may be mediated through the interaction of other systems such as heme oxygenase, primarily via upregulation of ho-1 gene expression in both sexes. Contrary to our previous study in liver of hyperoxia treated mice, current results might imply that at conventional oxygen conditions lungs of female mice with the emphasis on aging females, are better prepared for oxidative stress conditions through the increase of HO-activity

Structural and Functional Characterization of Ribosomal Protein Gene Introns in Sponges

Ribosomal protein genes (RPGs) are a powerful tool for studying intron evolution. They exist in all three domains of life and are much conserved. Accumulating genomic data suggest that RPG introns in many organisms abound with non-protein-coding-RNAs (ncRNAs). These ancient ncRNAs are small nucleolar RNAs (snoRNAs) essential for ribosome assembly. They are also mobile genetic elements and therefore probably important in diversification and enrichment of transcriptomes through various mechanisms such as intron/exon gain/loss. snoRNAs in basal metazoans are poorly characterized. We examined 449 RPG introns, in total, from four demosponges: Amphimedon queenslandica, Suberites domuncula, Suberites ficus and Suberites pagurorum and showed that RPG introns from A. queenslandica share position conservancy and some structural similarity with “higher” metazoans. Moreover, our study indicates that mobile element insertions play an important role in the evolution of their size. In four sponges 51 snoRNAs were identified. The analysis showed discrepancies between the snoRNA pools of orthologous RPG introns between S. domuncula and A. queenslandica. Furthermore, these two sponges show as much conservancy of RPG intron positions between each other as between themselves and human. Sponges from the Suberites genus show consistency in RPG intron position conservation. However, significant differences in some of the orthologous RPG introns of closely related sponges were observed. This indicates that RPG introns are dynamic even on these shorter evolutionary time scales