Methylation-dependent and independent regulatory regions in the Na,K-ATPase alpha4 (Atp1a4) gene may impact its testis-specific expression

Abstract

The α4 Na,K-ATPase is a sperm-specific protein essential for sperm motility and fertility yet little is known about the mechanisms that regulate its expression in germ cells. Here, the potential involvement of DNA methylation in regulating the expression of this sperm-specific protein is explored. A single, intragenic CpG island (Mα4-CGI) was identified in the gene encoding the mouse α4 Na,K-ATPase (Atp1a4), which displayed reduced methylation in mouse sperm (cells that contain α4) compared to mouse kidney (tissue that lacks α4 expression). Unlike the intragenic CGI, the putative promoter (the −700 to +200 region relative to the transcriptional start site) of Atp1a4 did not show differential methylation between kidney and sperm nevertheless it did drive methylation-dependent reporter gene expression in the male germ cell line GC-1spg. Furthermore, treatment of GC-1spg cells with 5-Aza2-Deoxycytidine led to upregulation of the α4 transcript and decreased methylation of both the Atp1a4 promoter and the Mα4-CGI. In addition, Atp1a4 expression in mouse embryonic stem cells deficient in DNA methytransferases suggests that both maintenance and de novo methylation are involved in regulating its expression. In an attempt to define the regulatory function of the Mα4-CGI, possible roles of the Mα4-CGI in regulating Atp1a4 expression via methylation-dependent transcriptional elongation inhibition in somatic cells and via its ability to repress promoter activity in germ cells were uncovered. In all, our data suggests that both the promoter and the intragenic CGI could combine to provide multiple modes of regulation for optimizing the Atp1a4 expression level in a cell type-specific manner.

Na,K-ATPase regulation in skeletal muscle

“…However, although these mechanisms have emerged as regulators of skeletal muscle adaptations to various physiological stimuli such as exercise ( 21), epigenetic regulation of NKA expression in skeletal muscle has surprisingly not been thoroughly examined to date. This is even more surprising since the data from nonmuscle cells and tissues suggest that epigenetic mechanisms regulate expression of ␣and ␤-subunits as well as FXYDs (19,190,308). Indeed, hypomethylation of promotor and intragenic regions of the ␣ 4 -gene in mouse sperm may explain why the ␣ 4subunit is expressed specifically in sperm (190).…”

“…This is even more surprising since the data from nonmuscle cells and tissues suggest that epigenetic mechanisms regulate expression of ␣and ␤-subunits as well as FXYDs (19,190,308). Indeed, hypomethylation of promotor and intragenic regions of the ␣ 4 -gene in mouse sperm may explain why the ␣ 4subunit is expressed specifically in sperm (190). In addition, promotor methylation reduces gene expression of the ␤ 1subunit in renal cancer cells (308).…”

Aberrant Epigenetic Gene Regulation in GABAergic Interneuron Subpopulations in the Hippocampal Dentate Gyrus of Mouse Offspring Following Developmental Exposure to Hexachlorophene

“…However, transcript downregulation of Dmrt1 was not sustained on PND 77 in the present study. The previous detection of methylation-sensitive and methylation-insensitive regulatory sequences for transcription in the gene promoter region ( Kumar et al , 2016 ) suggests the hypermethylation at methylation-insensitive CpG sites of Dmrt1 on PND 77 after developmental HCP exposure. With regard to Dlx4 , promoter region hypermethylation and transcript downregulation were sustained through PND 77, although these HCP-induced changes were not reflected in the hilar density of the DLX4 + cells.…”

Updates on immunological mechanistic insights and targeting of the oral lichen planus microenvironment

“…Chemokines are proinflammatory cytokines that move cells direction toward high concentration stimuli and can induce directional chemotaxis in nearby response cells ( 79 ), which can be divided into four categories, CC, CXC, C and CX3C, according to their structure. RANTES, also known as CCL5, belongs to the CC chemokine family and could recruit lymphocytes, mast cells, monocytes, and natural killer cells in OLP ( 3 ).…”