Cell Cycle Regulation by Kaposi’s Sarcoma-Associated Herpesvirus K-bZIP: Direct Interaction with Cyclin-CDK2 and Induction of

Antibody binding was detected using SuperSignal West Dura extended duration substrate kit (Pierce) or using an Odyssey imager. Bars indicate the levels of induction of luciferase activity … Cell cycle progression is critically regulated by sequential activation of cyclins and cyclin-dependent kinases (Cdks). (B) Same as panel A, but with … , there was a rapid rise of the level of K-bZIP within 12 h, consistent with its classification as an early-lytic gene product. For the screen, we used SLK cells stably infected with a recombinant KSHV (rKSHV.219) which during latency constitutively expresses green fluorescent protein (GFP) under the control of the cellular EF-1α promoter, and upon reactivation the red fluorescent protein (RFP) from the promoter of the viral early lytic gene PAN [34].

and ), the oligomerization state of RAP was not known. (C and D) Effects of vIRF4 on the expression of cyclin D1 and other β-catenin/TCF-regulated genes. However, one caveat should be borne in mind, i.e., that our hypothesis is founded on the premise that CDK1-cyclin B and CDK2-cyclin E complexes exhibit similar substrate specificities in vitro (reference 77 and our unpublished results). 4). This result implied that ORF50 protein regulates two types of ORF50 REs (Fig. Thus, such point mutations that disrupt DNA binding could also reduce the transcriptional function in activating the ORF57 and vMIP1 promoters by influencing the interaction with RBP-Jκ.

HHV-6B induces p53 Ser392 phosphorylation by an atypical pathway independent of CK2 and p38 kinases [28]. By use of the dual probe for K8 and K8.1, it was shown that PAA inhibited the expression of the 0.9-kb K8.1 late mRNA, but had little effect on expression of the K8 early mRNA (Fig. A JSC1 cell extract prepared after a 40-h TPA treatment was used for cross-linking and immunoprecipitation. No significant differences were seen for LANA and vCyclin expression in BC3-shRNA-ctl and BC3-shRNA-K8 cells. Kaposi’s sarcoma-associated herpesvirus (KSHV) establishes persistent latent infection in immunocompetent hosts. At 12 h postinduction, the DE mDBP gene was stimulated approximately fourfold; however, the late MCP transcript was absent.

6B). While they are generally not expressed in PEL cells during latency, they may play a role in mitogenesis in KS tumors. Again, no fatty acid blocked the KSHV lytic cycle (, bottom panel, and D, bottom panel). Semiquantitative RT-PCR was performed essentially as described previously (24). To determine the levels of miR-HSURs in HVS-infected cells, we size selected small RNAs, constructed a cDNA library, and performed high-throughput sequencing (6). We found that one of the SIRTs, SIRT1, binds to the RTA promoter to mediate KSHV latency.

Regarding egress, our observations indicate that primary envelopment of nucleocapsids occurred at the inner leaflet of the nuclear membrane by budding into the perinuclear cisterna. (A) Schematic diagram showing the region of ORF50 promoter sequences used as wild-type (WT) and linker-scanning mutant competitors in the EMSA illustrated in panel B. Briefly, 6-μm thin sections of formalin-fixed paraffin-embedded tissue were deparaffinized, rehydrated, and pretreated with an antigen retrieval protocol by using microwave irradation. Cytospin preparations of cultured cells were fixed for 10 minutes in 50:50 acetone:methanol and air-dried. 3). ↵*Corresponding author.

More recently, they have shown that the arrest at the G1/S phase involved a pathway independent of p53 (53). Growth-arrested cells were stimulated with medium containing 10% serum and doxycycline. We have characterized an unknown open reading frame, Orf49, which lies adjacent and in the opposite orientation to Orf50. A short fragment of the promoter, 134 nucleotides upstream of the translational start of ORF50, retained basal uninduced activity and conferred maximal responsiveness to sodium butyrate. In the FANTOM 3 data set, at least 25% of confirmed murine coding RNAs have well-characterized overlapping antisense transcripts: when fragmentary cDNAs are included, this percentage can rise as high as 72% (23). The Rta and p27 localization and DAPI-stained nuclei were visualized by confocal microscopy.

Of note, our results indicate that although vBcl-2 is expressed at low levels, it has a critical role in the lytic phase. We have identified a multifunctional regulatory region, present in amino acids (aa) 520 to 535 of ORF50 protein, that controls DNA binding and protein stability. RTA functions as E3 Ub-ligase for MyD88. Genetic studies have demonstrated that ICP8 is required for the localization of viral replication and cellular proteins to the replication compartments [18], [19]. 3F).

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