| OCR Text |
Show 109 developmental stages after E14.5. 2. The first wave of CART+/Pmch+ neurons are exclusively localized in the medial hypothalamus around the 3rd ventricle at the time when many Pmch+ neurons are already localized in the LH (Brischoux et al., 2001). 3. Cartpt expression is present in the Pvp at P22, which is lost in Lef1CKO (not shown). 4. In Pmch-/- rats, loss of Pmch does not cause reduced expression of Cartpt (Mul et al., 2010), suggesting that Cartpt expression does not depend on Pmch. 5. Master transcriptional factors can actively maintain the expression of terminal identity features of individual postmitotic neurons throughout life (Deneris and Hobert, 2014). If Lef1 activates Cartpt expressions after neurogenesis is already complete, Lef1 may also activate Pmch expression postnatally. In fact, Pmch expression in rats has been shown to increase gradually in the early postnatal stage but rise abruptly at weaning, followed by a constant level in adulthood (Presse et al., 1992). Alternatively, there may be continuous postnatal cell divisions in the PVp, which was not recognized before, or failed to be labeled by BrdU pulse-chase (see section 1.4). In fact, I showed that long-lived quiescent Wntresponsive cells in the zebrafish hypothalamus are difficult to label by BrdU (not shown). The ideal experiment would be making a Lef1CreERT2 mouse line, crossed with a lineage reporter, then injected with tamoxifen postnatally followed by tissue fixation at different stages. If there are more recombined cells at a later stage than an earlier stage, Lef1-derived progenitor proliferation will be confirmed. |
