AUTHOR=Patyal Pankaj , Fil Daniel , Wight Patricia A. 

TITLE=Plp1 in the enteric nervous system is preferentially expressed during early postnatal development in mouse as DM20, whose expression appears reliant on an intronic enhancer

JOURNAL=Frontiers in Cellular Neuroscience

VOLUME=Volume 17 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/cellular-neuroscience/articles/10.3389/fncel.2023.1175614

DOI=10.3389/fncel.2023.1175614

ISSN=1662-5102

ABSTRACT=Recently, the myelin proteolipid protein gene (Plp1) was shown to be expressed in glia of the enteric nervous system (ENS) in mouse. However, beyond this, not much is known about its expression in intestine. To address this matter, we investigated Plp1 expression at the mRNA and protein levels in intestine from mice at different ages (postnatal days 2, 9, 21 and 88). Here we show that Plp1 expression preferentially occurs during early postnatal development, primarily as the DM20 isoform. Western blot analysis indicated that DM20 migrated according to its formula weight when isolated from intestine. However, curiously, mobilities of both PLP and DM20 were faster than expected when procured from brain. The 6.2hPLP(+)Z/FL transgene, which uses the first half of the human PLP1 gene to drive expression of a lacZ reporter gene, recapitulated the developmental pattern observed with the native gene in intestine, indicating that it can be used as a proxy for Plp1 gene expression. As such, the relative levels of beta-galactosidase (beta-gal) activity emanating from the 6.2hPLP(+)Z/FL transgene suggest that Plp1 expression is highest in duodenum, and decreases successively along the segments, towards the colon. Moreover, removal of the wmN1 enhancer region from the transgene (located within Plp1 intron 1) resulted in a dramatic reduction in both transgene mRNA levels and beta-gal activity in intestine, throughout development, suggesting that this region contains a regulatory element crucial for Plp1 expression. This is consistent with earlier work in both the central and peripheral nervous systems, indicating that it may be a common (if not universal) means by which Plp1 gene expression is governed.