RESUMO
Members of the PRDM protein family have been shown to play important roles during embryonic development. Previous in vitro and in situ analyses indicated a function of Prdm6 in cells of the vascular system. To reveal physiological functions of Prdm6, we generated conditional Prdm6-deficient mice. Complete deletion of Prdm6 results in embryonic lethality due to cardiovascular defects associated with aberrations in vascular patterning. However, smooth muscle cells could be regularly differentiated from Prdm6-deficient embryonic stem cells and vascular smooth muscle cells were present and proliferated normally in Prdm6-deficient embryos. Conditional deletion of Prdm6 in the smooth muscle cell lineage using a SM22-Cre driver line resulted in perinatal lethality due to hemorrhage in the lungs. We thus identified Prdm6 as a factor that is essential for the physiological control of cardiovascular development.
Assuntos
Sistema Cardiovascular/embriologia , Proteínas Repressoras/fisiologia , Animais , Sequência de Bases , Northern Blotting , Southern Blotting , Padronização Corporal , Diferenciação Celular , Proliferação de Células , Primers do DNA , Camundongos , Camundongos Knockout , Músculo Liso/citologia , Neovascularização Fisiológica , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , Proteínas Repressoras/genéticaRESUMO
The doublecortin (DCX) gene encodes a 40-kDa microtubule-associated protein specifically expressed in neuronal precursors of the developing and adult CNS. Due to its specific expression pattern, attention was drawn to DCX as a marker for neuronal precursors and neurogenesis, thereby underscoring the importance of its promoter identification and promoter analysis. Here, we analysed the human DCX regulatory sequence and confined it to a 3.5-kb fragment upstream of the ATG start codon. We demonstrate by transient transfection experiments that this fragment is sufficient and specific to drive expression of reporter genes in embryonic and adult neuronal precursors. The activity of this regulatory fragment overlapped with the expression of endogenous DCX and with the young neuronal markers class III beta-tubulin isotype and microtubule-associated protein Map2ab but not with glial or oligodendroglial markers. Electrophysiological data further confirmed the immature neuronal nature of these cells. Deletions within the 3.5-kb region demonstrated the relevance of specific regions containing transcription factor-binding sites. Moreover, application of neurogenesis-related growth factors in the neuronal precursor cultures suggested the lack of direct signalling of these factors on the DCX promoter construct.