Project description:Cortical development is a complex process involving the generation of neuronal progenitors, which proliferate and migrate to form the stratified layers of the maturing cortex. To identify microRNAs (miRNAs) and genes that may be important during early cortical development, we analyzed the expression profiles of rat neuronal progenitors obtained at embryonic day 11 (E11), E12 and E13 using microarrays. Neuronal progenitors were purified from telencephalic dissociates with a positive-selection strategy using surface labeling tetanus-toxin and cholera-toxin and fluorescence-activated cell sorting. We identified classes of miRNAs and mRNAs that were up-regulated or down-regulated in these neuronal progenitors as cortical development progressed from E11 to E13. We present data that supports a regulatory role for miRNAs during the transition from neuronal progenitors into differentiating cortical neurons. Experiment Overall Design: Flow cytometry was used to isolate tetanus toxin+ and cholera toxin+ neuronal progenitors from embryonic days 11, 12 and 13 rat telencephalon. 4 biological replicates were obtained for each group using a pooled litters for each biological replicate on different prepararation days
Project description:Here we compared the expression of an engineered kidney tissue, created by recombining an in vitro budded Wolffian duct with fresh E13 metanephric mesenchyme, with that of three in vivo rat embryonic kidney timepoints (E13, E18, and week 4) Keywords: time course
Project description:The inner ear in mammals is derived from a simple ectodermal thickening called the otic placode. Through a series of complex morphological changes, the placode forms the mature inner ear comprising of the auditory organ (cochlea) and the vestibular/balance organs (utricle, saccule, and three semi-circular canals). The vast majority of genes known to be involved during inner ear development have been found through mutational screens or by chance. To identify genes that can serve as novel candidates required for inner ear development, and also candidate genes for uncloned human deafnesses, inner ear tissues from mouse embryos from E9 to E15 were microdissected and expression-profiled at half-day intervals. Also profiled was the non-inner ear mesenchymal tissue surrounding the inner ear tissue. Various patterns of gene expression were identified, and significant biological pathways that these genes represented were identified. Also identified were mouse genes whose human orthologs are located within uncloned non-syndromic deafness intervals, thus serving as candidates for sequence analysis. Experiment Overall Design: Inner ear tissues from E9 to E15 were microdissected at half-day intervals. E9 is the earliest stage when the otic placode is clearly visible and able to be microdissected cleanly. E15 is the stage when all the organs of the inner ear have become established, as have the sensory hair and non-sensory support cells within those organs. For each of the stages from E9 to E10, whole inner ears were profiled. For each of the stages from E10.5 to E12, the primordial cochlear and vestibular organs were profiled separately. For each of the stages from E12.5 to E15, the cochlea and the saccule were profiled separately, whereas the utricle and the three ampullae were combined and profiled together. Any given tissue from any given stage was a collection of anywhere between 4 to 17 identical tissues, and was obtained in duplicate (i.e. from different litters). Hence, a total of 58 inner ear samples were obtained. Moreover, non-inner ear tissue found in the immediate vicinity of inner ear tissue was also obtained and profiled. Specifically, all non-inner ear tissue from E9 was profiled in duplicate. Non-inner ear tissue from E9.5 to E10.5 was pooled and profiled together (in duplicate), whereas that from E11 to E15 was pooled and profiled together (also in duplicate). Therefore, a total of 6 non-inner samples were obtained.