Abstract
In this study, we investigated the distribution, localization and several various functions of TrkC receptors during development of the Monodelphis opossum brain. Western blotting analysis showed that two different forms of the TrkC receptor, the full-length receptor and one of its truncated forms, are abundantly expressed in the opossum brain. The expression of TrkC receptors was barely detected in the brain of newborn opossums. At postnatal day (P) 3, the expression of full-length TrkC remained at low levels, while moderate expression of the TrkC truncated form was detected. The expression levels of both forms of this protein gradually increased throughout development, peaking at P35. We found that in different neocortical areas located both at the rostral and caudal regions of the cortex, up to 98% of BrdU-labeled cells forming cortical layers (II-VI) had prominently expressed TrkC. To assess which developmental processes of cortical cells are regulated by TrkC receptors, three different shRNAs were constructed. The shRNAs were individually tested in transfected cortical progenitor cells grown on culture plates for 2 days. The effects of the shRNA-TrkC constructs were similar: blockade of TrkC receptors decreased the number of Ki67-positive and apoptotic cells, and it did not change the number of TUJ-positive neurons in vitro. Thus, the lack of TrkC receptors in cultured progenitor cells provided insight on the potential role of these receptors in the regulation of proliferation and cell survival but not in the differentiation of cortical cells.
Highlights
The highly diversified mammalian infraclass Marsupialia split from the infraclass Eutheria at least 125 million years ago, and since they have evolved in parallel [1], independently developing similar ecological specializations
The expression of tropomyosinreceptor-kinase C (TrkC) receptors was examined from postnatal (P) day 1 (P1; day of birth) and continued until P3, P7, P12, P20, P35, P60 or P400 (13 months)
We investigated the expression of full-length and truncated TrkC receptors during opossum brain development
Summary
The highly diversified mammalian infraclass Marsupialia split from the infraclass Eutheria at least 125 million years ago, and since they have evolved in parallel [1], independently developing similar ecological specializations. Many Didelphid species, including the gray short-tailed opossum Monodelphis domestica show anatomical features that are similar to those of early marsupials and eutherians [2]. The general pattern of brain development in marsupials is similar to that in eutherians. The sequence of neocortical development in the gray short-tailed opossum (Monodelphis domestica) is similar to that observed in other mammals [9,10]. The role of neurotrophin receptors in the mechanisms of marsupial brain development remains unknown. Numerous studies in the eutherian species have shown that the expression of neurotrophins starts at a very early stage of brain development [11,12]. Different neurotrophins and their receptors are selectively expressed at various stages of development, and they control crucial developmental processes such as cell proliferation and differentiation, survival, synaptogenesis and neuronal morphology [13,14,15,16,17]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
