Nuclear Matrix (NuMat) is the structural and functional framework of the nucleus. It has been shown that attachment ofchromatin to NuMat brings significant regulation of the transcriptional activity of particular genes; however, key componentsof NuMat involved in this process remain elusive. We have identified Lid (Little imaginal discs) as one of thecomponents of NuMat. It belongs to the TrxG group of proteins involved in activation of important developmental genes.However, unlike other activator proteins of TrxG, Lid is a Jumonji protein involved in H3K4me3 demethylation. Here, wereport the association of Lid and its various domains with NuMat which implicates its structural role in chromatinorganization and epigenetic basis of cellular memory. We have found that both N and C terminal regions of this protein arecapable of associating with NuMat. We have further mapped the association of individual domains and found that, PHD,ARID and JmjC domains can associate with NuMat individually. Moreover, deletion of N-terminal PHD finger does notalter Lid’s NuMat association implying that although it is sufficient, yet, it is not necessary for Lid’s structural role inNuMat. Based on our findings, we hypothesize that C terminal region of Lid which contains PHD fingers might beresponsible for its NuMat association via protein–DNA interactions. However, for the N terminal region harboring both aPHD and an ARID finger, Lid anchors to the NuMat via both protein-protein and protein-DNA interactions. The associationof JmjC domain with NuMat is the first report of the association of a demethylase domain with NuMat suggesting that Lid,a demethylase, being part of NuMat might be involved in regulating the chromatin dynamics via its NuMat association.
Volume 46, 2020
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