Abstract
HMGA2 is a non-histonic nuclear protein belonging to the HMGA family, characterized by the small dimensions (less than 30 kDa), the high electrophoretic mobility and for its role as indirect regulator of transcription. Its functional features are due to the ability to interact with the DNA, thanks to three HMGA characteristic domains (the AT-hooks, able to recognize and specifically bind AT-rich regions in the minor groove of the DNA double strand), and also to the faculty to modulate the activity of proteins by specific interactions with them.
In our lab a hmga2 homolog was cloned from Xenopus laevis, sequenced and, subsequently characterized for its spatial and temporal expression in Xenopus
laevis embryogenesis; the functional role of the protein was approached by
loss-of-function experiments, achieved with microinjections of morpholino antisense oligonucleotides.
In my thesis, I worked to confirm the results of preliminary loss-of-function studies, and to verify the specificity of the observed effects on Xenopus laevis embryonic development as a consequence of hmga2 knock down. To achieve this goal, I used a morpholino antisense oligonucleotide different from the one used previously, targeting the 5’UTR rather than the translation initiation site on the hmga2 mRNA. The morpholino was injected together with mRNA of lacZ and GFP genes in the animal zone of one of the dorsal blastomeres of 4-cell stage embryos. Whole mount in situ hybridizations were performed on embryos at different developmental stages with specific probes for neural crest cells.
These experiments allowed to confirm the results of the previous tests and enforced the hypothesis of an hmga2 involvement in the neural crest molecular processes during Xenopus laevis embryonic development.
