GSE52606
Novel primate miRNAs co-evolved with ancient target genes in germinal zone specific expression patterns [miRNA-Seq]
Major non primate-primate differences in corticogenesis include the dimensions, precursor lineages and developmental timing of the germinal zones (GZ). microRNAs (miRNAs) of laser dissected GZ compartments and cortical plate (CP) from embryonic E80 macaque visual cortex were deep sequenced. The CP and the GZ including Ventricular Zone (VZ), outer and inner subcompartments of the Outer SubVentricular Zone (OSVZ) in area 17 displayed unique miRNA profiles. miRNAs present in primate, but absent in rodent, contributed disproportionately to the differential expression between GZ sub-regions. Prominent among the validated targets of these miRNAs were cell-cycle and neurogenesis regulators. Co-evolution between the emergent miRNAs and their targets suggested that novel miRNAs became integrated into ancient gene circuitry to exert additional control over proliferation. We conclude that multiple cell-cycle regulatory events contribute to the emergence of primate-specific cortical features, including the OSVZ, generated enlarged supragranular layers, largely responsible for the increased primate cortex computational abilities. Overall design: Seven brain regions (VZ17, OSVZ17int, OSVZ17ext, CP17, VZ18, OSVZ18, CP18). OSVZ17int corresponds to the inner (apical) third of OSVZ 17 and OSVZ17ext to the most outer (basal) third of OSVZ 17, located immediately below the Outer Fiber Layer (Smart et al., 2002; Betizeau et al., 2013)