Cytomegalovirus cyclin-dependent kinase ortholog vCDK/pUL97 undergoes regulatory interaction with human cyclin H and CDK7 to codetermine viral replication efficiency

The Interactive Complex between Cytomegalovirus Kinase vCDK/pUL97 and Host Factors CDK7–Cyclin H Determines Individual Patterns of Transcription in Infected Cells

“…In essence, the current RNA-seq analysis aligned with the previous findings of our group, strongly suggesting a functional interaction between cyclin H, CDK7, and vCDK/pUL97 [11,21,22], which potentially regulates various aspects of gene transcription. The main findings of the present RNA-seq analysis were as follows: (i) all chosen conditions of kinase inhibition or cyclin H KO showed a substantial change in transcriptional patterns in HCMV-infected cells; (ii) in quantitative terms, the cyclin H KO exerted a more drastic transcriptional change than CDK7 or vCDK/pUL97 inhibition; (iii) according to the GO data, those altered processes referring to cell cycle regulation were the only group found associated with all relevant conditional changes of HCMV infection, i.e., CDK7, vCDK/pUL97 inhibition, or cyclin H KO; (iv) the identified altered CDK7-specific processes (LDC4297) were found in an overlap with those detected for cyclin H KO; (v) however, within the altered vCDK/pUL97-specific processes (MBV), particularly the DNA metabolic processes, were not paralleled by cyclin H KO or CDK7 inhibition; (vi) concerning the regulation of individual transcripts, distinctly different patterns were detected, including one pattern in which the indicated transcripts were broadly influenced by CDK7, cyclin H, and pUL97, or patterns that indicated transcripts showing an exclusive regulatory linkage to cyclin H and pUL97, or others; and (vii) a bioinformatic model provided a structural rationale for the experimental observation that both CDK7 and vCDK/pUL97 have an impact on RNAP II activation in HCMV-infected cells.…”

“…This experimental structure contained CDK7, MAT1, and cyclin H, but lacked information about the putative position of pUL97. Our previous molecular modeling study suggested that the primary interaction motif of pUL97(231-280) used the same binding pocket as MAT1 for targeting the cyclin H-CDK7 complex [22]. The modeling indicated that this binding mode of pUL97(231-280) was also largely compatible with the PIC geometry (Figure 4B).…”

“…Recent investigations provided evidence that the vCDK/pUL97 kinase activity is coregulated through cyclin H binding and that the interaction of this complex with CDK7 can lead to its trans-stimulation (at least when measured in activity assays in vitro). Specifically, this finding prompted us to address the question of whether vCDK/pUL97, either in the context of CDK7/cyclin H or independent of these host factors, may contribute to the control of transcriptional activity in HCMV-infected cells [10,11,22,23]. To this end, we generated experimental conditions described previously, which included a transient knockout of cyclin H, specific inhibition of vCDK/pUL97 by maribavir (MBV), or inhibition of host CDK7 by LDC4297.…”

‘Getting Better’—Is It a Feasible Strategy of Broad Pan-Antiherpesviral Drug Targeting by Using the Nuclear Egress-Directed Mechanism?

“…Although the experimental proof of a direct binding of host kinases to the herpesviral core NECs has not been successful for some time, the functional studies on NEC regulation strongly substantiated this statement (see numerous reviews: [ 45 , 48 , 50 , 62 , 64 , 126 , 127 , 128 , 129 , 130 , 131 , 132 ]). It became increasingly clear that, although the association of PKC could not be directly linked with functional importance, other host and viral kinases played a very crucial role in the regulatory phosphorylation of NEC proteins [ 125 , 133 , 134 , 135 ] and nuclear lamins [ 50 , 56 , 58 ].…”

An Antiherpesviral Host-Directed Strategy Based on CDK7 Covalently Binding Drugs: Target-Selective, Picomolar-Dose, Cross-Virus Reactivity

“…In particular, concerning the role of CDK7, it has previously been demonstrated that a functional depletion of CDK7 can be cross-compensated by related CDK-cyclin complexes [ 31 ] and is even tolerated in the non-embryonal adult tissues of knock-out mice [ 42 ]. On the other hand, CDK7 activity proved to be strictly required for the high efficiency of viral replication [ 41 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ]. Interestingly, although the depletion of CDK7 function may lead to drastic cytotoxic effects and apoptosis in melanoma cells [ 51 ], this was not the case in non-tumor cells or herpesvirus-infected cells or mice [ 52 ].…”