Sox2 and Pax6 Play Counteracting Roles in Regulating Neurogenesis within the Murine Olfactory Epithelium
Fig 3
Identification of cellular targets for replication-incompetent retroviruses, during lesion-induced regeneration of the OE.
(A-F) At 1 day post-MeBr lesion GBCs and duct/gland cells are predominant proliferating populations and putative retroviral targets as shown by immunostaining of tissue sections of OE from 1 day post-MeBr lesion with antibodies to Sox2 (which mark GBCs) and to Sox9 (which marks gland/duct cells) along with anti-CK14 and Ki-67, the latter marking proliferating cells. Single solid arrows mark Ki-67 (+), dividing cells that are Sox2 (+)/CK14 (-) in A-C and Sox9 (-)/CK14 (-) in D-F, and are found at a remove superficial to the basal lamina and correspond to GBCs or HBCs caught in transition to GBCs. All of the CK14 (+) cells are also Sox2 (+). In A-C, the solid arrow with one asterisk indicates a dividing HBC, while in D-F the solid arrow with two asterisks marks an HBC that is not dividing but now expresses Sox9, in addition to the Sox2 expression documented above. The presence of Sox2 (+)/Sox9 (+) basal cells may represent HBCs that are differentiating into duct/gland cells, which is observed after MeBr lesion (Leung et al., 2007). In A-F the hollow arrows indicate a proliferating putative duct/gland cell (in D-C) and a marker-confirmed duct/gland cell (in D-F). (G-I) Staining of sections of the normal mouse olfactory epithelium with Sox2, Sox9, and CK14 to mark specific cell types along with markers of proliferation, either Ki-67 labeling or EdU incorporation, for comparison with the composition of the epithelium after injury. On the basis of these staining patterns, Sox2 (+) cells located at a distance superficial to the basal lamina with weak or no CK14 (+) labeling are classified as GBCs, while those basal cells that are attached to the basal lamina and strongly positive for CK14 are identified as HBCs. Duct/gland cells or cells that are Sox9 (+) form a separate category. (J) The criteria enumerated above were used to count the percent of dividing cells that are GBCs, which are the vast majority under the lesion conditions used here. Dashed lines indicate the basal lamina. Scale bar in K corresponds to 10 μm and applies to all photomicrographs.