Functional Analysis of KAP1 Requirements for HIV-1 Transcription and Latency Reactivation
type: CreativeWork
description: HIV-1 latency maintenance and reactivation are regulated by several viral and host factors. One such regulator is Krüppel-associated box (KRAB)-associated protein 1 (KAP1: also named TRIM28 or TIF1β). While initial studies have revealed KAP1 to be a positive regulator of latency reversal in transformed and primary CD4+ T cells, subsequent studies have proposed KAP1 to be a repressor required for latency maintenance. Given this discrepancy, here we re-examine KAP1 transcription regulatory functions using a chemical genetics strategy to acutely deplete KAP1 expression to avoid the accumulation of indirect effects. KAP1 acute loss dampened HIV-1 promoter activity in response to activating signals, a function that can be restored upon complementation with exogenous KAP1, thus revealing KAP1-mediated activation is on target. By combining comprehensive KAP1 domain deletion and mutagenesis in a cell-based reporter assay, I genetically defined the RING finger domain and an Intrinsically Disordered Region as key activating features. However, KAP1 acute loss in a physiological relevant model, reveals limitations compared to chronic silencing of KAP1 in the same system. I also identified a potential co-factor MAGE-D2 from previous biochemical and genetic screens that interacts with KAP1. MAGE-D2 mimics KAP1s ability to activate HIV-1 latency reactivation in response to stimulation suggesting they form a complex to regulate the proviral genome. Together, this study solidifies the notion that KAP1 activates HIV-1 transcription by exploiting its multi-domain protein arrangement through previously unknown domains and functions. Also, this study highlights the need for better techniques to assess the direct consequence of KAP1 loss.
abstract: HIV-1 latency maintenance and reactivation are regulated by several viral and host factors. One such regulator is Krüppel-associated box (KRAB)-associated protein 1 (KAP1: also named TRIM28 or TIF1β). While initial studies have revealed KAP1 to be a positive regulator of latency reversal in transformed and primary CD4+ T cells, subsequent studies have proposed KAP1 to be a repressor required for latency maintenance. Given this discrepancy, here we re-examine KAP1 transcription regulatory functions using a chemical genetics strategy to acutely deplete KAP1 expression to avoid the accumulation of indirect effects. KAP1 acute loss dampened HIV-1 promoter activity in response to activating signals, a function that can be restored upon complementation with exogenous KAP1, thus revealing KAP1-mediated activation is on target. By combining comprehensive KAP1 domain deletion and mutagenesis in a cell-based reporter assay, I genetically defined the RING finger domain and an Intrinsically Disordered Region as key activating features. However, KAP1 acute loss in a physiological relevant model, reveals limitations compared to chronic silencing of KAP1 in the same system. I also identified a potential co-factor MAGE-D2 from previous biochemical and genetic screens that interacts with KAP1. MAGE-D2 mimics KAP1s ability to activate HIV-1 latency reactivation in response to stimulation suggesting they form a complex to regulate the proviral genome. Together, this study solidifies the notion that KAP1 activates HIV-1 transcription by exploiting its multi-domain protein arrangement through previously unknown domains and functions. Also, this study highlights the need for better techniques to assess the direct consequence of KAP1 loss.
author: Randolph, Keyera
language: en
keywords: HIV-1, Transcriptional Activation, Tripartite Motif-Containing Protein 28
date published: 2026-06-15T19:42:14Z
date modified: 2026-07-24T05:52:15Z
provider: University of Texas Southwestern Medical Center
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Texas Southwestern Medical Center

PropertyValue
property ID: Handle
value: https://hdl.handle.net/2152.5/10803