23 research outputs found
Characterization of tailor-made copolymers of oligo(ethylene glycol) methyl ether methacrylate and N,N-dimethylaminoethyl methacrylate as nonviral gene transfer agents: Influence of macromolecular structure on gene vector particle properties and transfection efficiency.
The non-coding RNAs of the H19-IGF2 imprinted loci: A focus on biological roles and therapeutic potential in Lung Cancer
Regulatory role of Pax6 on cell division cycle associated 7 and cortical progenitor cell proliferation
Forebrain development is controlled by a set of transcription factors which are
expressed in dynamic spatiotemporal patterns in the embryonic forebrain and are
known to regulate complex gene networks. Pax6 is a transcription factor that
regulates corticogenesis and mutations affecting Pax6 protein levels cause
neurodevelopmental defects in the eyes and forebrain in both humans and mice. In
previous studies, it was shown that the graded expression pattern of Pax6 protein,
which is high rostro-laterally to low caudo-medially in the cerebral cortex, is critical
for its control of cell cycle progression and proliferation of cortical progenitors.
However the underlying mechanisms are still unclear.
Based on a microarray analysis carried out in our laboratory, a number of cell cycle-related
candidate genes that may be affected by Pax6 have been identified. One such
gene, Cell division cycle associated 7 (Cdca7) is expressed in a counter-gradient
against that of Pax6. In my current study, I found that Cdca7 mRNA expression in
the telencephalon is upregulated in Pax6 null (Small eye) mutants and downregulated
in mice that overexpress PAX6 (PAX77) across developing time points from E12.5 to
E15.5. There are several potential Pax6 binding motifs located in the genomic locus
upstream of Cdca7. However, by chromatin immunoprecipitation, it is showed that
none of the predicted binding sites are physically bound by Pax6. Promoter luciferase
assays using fragments combining five suspected binding motifs show that Pax6 is
functionally critical.
Cdca7 is also identified as a Myc and E2F1 direct target and is upregulated in some
tumours but its biological role is not fully understood. Current work using in utero
electroporation to overexpress Cdca7 around the lateral telencephalon, where Cdca7
expression levels are normally low, tested the effects on the proliferation and
differentiation of cortical progenitor cells in this region. In E12.5 mice embryos,
overexpression of Cdca7 protein causes fewer intermediate progenitor cells and post-mitotic
neurons to be produced but these effects were not found in E14.5 embryos.
This result implies that Cdca7 may affect cell fate decision during cortical
development
Cryptic diversity in Australian stick insects (Insecta; Phasmida) uncovered by the DNA barcoding approach
The barcoding approach was applied to analyze 16 Australian morphospecies of the order Phasmida, with the aim to test if it could be suitable as a tool for phasmid species identification and if its discrimination power would allow uncovering of cryptic diversity. Both goals were reached. Eighty-two specimens representing twelve morphospecies (Sipyloidea sp. A, Candovia annulata, Candovia sp. A, Candovia sp. B, Candovia sp. C, Denhama austrocarinata, Xeroderus kirbii, Parapodacanthus hasenpuschorum, Tropidoderus childrenii, Cigarrophasma tessellatum, Acrophylla wuelfingi, Eurycantha calcarata) were correctly recovered as clades through the molecular approach, their sequences forming monophyletic and well-supported clusters. In four instances, Neighbor-Joining tree and barcoding gap analyses supported either a specific (Austrocarausius mercurius, Anchiale briareus) or a subspecific (Anchiale austrotessulata, Extatosoma tiaratum) level of divergence within the analyzed morphospecies. The lack of an appropriate database of homologous coxI sequences prevented more detailed identification of undescribed taxa