INTS7

INTS7 is a nuclear backbone subunit of the Integrator complex with conserved roles in cell proliferation and signaling during development, established by its Drosophila ortholog deflated whose loss produces pleiotropic developmental defects consistent with perturbed cell signaling and proliferation (PMID:19326441). In mammalian cells, INTS7 supports proliferation by suppressing oxidative stress: it physically interacts with ABCD3 in bone marrow mesenchymal stem cells, and disruption of this interaction raises ROS and γ-H2AX, induces apoptosis, and shifts the balance from osteoblastic toward adipogenic differentiation (PMID:34880777). INTS7 stability is governed by BAG3, which binds INTS7 and prevents its proteasomal ubiquitination; restoring INTS7 rescues the proliferation deficit caused by BAG3 loss, placing INTS7 downstream of BAG3 in a pathway controlling stem cell expansion through oxidative stress control (PMID:37576499). INTS7 also operates at the chromatin/genome-stability interface: its loss in embryonic stem cells elevates DNA damage, drives Kap1 phosphorylation, increases chromatin accessibility at MERVL retrovirus loci, and activates a p53–Dux transcriptional axis to induce MERVL expression alongside caspase-3 cleavage and anastasis (PMID:40842237). At the transcriptional level, INTS7 is regulated from a bidirectional intergenic promoter shared with CDT2, where B-Myb, c-Myb, and p53 down-regulate INTS7 expression (PMID:18213392).

1. 2008 Medium

   Established how INTS7 itself is transcriptionally controlled, revealing asymmetric regulation from a promoter region shared with a neighboring gene.

   Evidence Luciferase reporter assays with multiple transcription factors and RT-PCR validation in A549 cells

   PMID:18213392

   Open questions at the time

   • Does not address INTS7 protein function
   • Regulation shown on reporters, not at the endogenous locus across cell types
2. 2009 Medium

   Defined a conserved in vivo requirement for the INTS7 ortholog in development, localizing it to the nucleus and linking it to cell signaling and proliferation.

   Evidence GFP localization and loss-of-function phenotypic analysis of four mutant alleles in Drosophila

   PMID:19326441

   Open questions at the time

   • Molecular mechanism of the developmental defect not resolved
   • Integrator-complex biochemical role not directly tested
3. 2021 Medium

   Identified a direct physical partner (ABCD3) and connected INTS7 to oxidative stress suppression governing stem cell proliferation and differentiation fate.

   Evidence Reciprocal co-IP, siRNA knockdown, proliferation, differentiation staining, and ROS/γ-H2AX assays in mouse BM-MSCs

   PMID:34880777

   Open questions at the time

   • Mechanism by which the INTS7–ABCD3 interaction controls ROS unknown
   • Relationship to canonical Integrator function not established
4. 2023 Medium

   Placed INTS7 in a regulatory hierarchy by showing BAG3 stabilizes it against ubiquitin-mediated degradation, with epistasis confirming INTS7 is the functional effector downstream of BAG3.

   Evidence Co-IP, protein half-life and ubiquitination assays, plus INTS7 overexpression rescue in BM-MSCs

   PMID:37576499

   Open questions at the time

   • Identity of the ubiquitin ligase acting on INTS7 unknown
   • Whether BAG3 acts as a direct chaperone or via co-chaperones unresolved
5. 2025 Medium

   Connected INTS7 to genome stability and stem cell fate, showing its loss triggers DNA damage and a chromatin/p53–Dux program driving endogenous retrovirus transcription.

   Evidence Genome-wide knockout screen with chromatin accessibility, Kap1 phosphorylation, p53–Dux pathway and caspase-3 readouts in mouse ESCs

   PMID:40842237

   Open questions at the time

   • Whether DNA damage is a direct consequence of lost Integrator activity not dissected
   • Mechanism of chromatin opening at MERVL loci unresolved
6. 2025 Low

   Extended the proliferative role of INTS7 to a disease context, showing it promotes cell cycle progression in lung adenocarcinoma.

   Evidence siRNA/shRNA knockdown with proliferation and flow cytometry cell cycle analysis in LUAD lines

   PMID:40875878

   Open questions at the time

   • No pathway-level mechanism resolved
   • Single study, standard knockdown without orthogonal validation

• How INTS7's role as an Integrator backbone subunit in snRNA processing/RNA Pol II regulation mechanistically connects to its observed roles in oxidative stress, genome stability, and proliferation remains unresolved.
• No direct biochemical link between Integrator catalytic function and the ROS/DNA-damage phenotypes
• Substrate-level role within the Integrator complex not characterized in this corpus