Digital Platforms and Market Dominance: Insights from a Systematic Literature Review and Avenues for Future Research

Companies that take advantage of digital platforms have rapidly gained a dominant position in their respective markets. While research on digital platforms yielded new insights into winner-take-all markets, envelopment, openness, or governance, no study provided a framework that integrates those aspects and links them to market dominance. We, therefore, conduct a literature review to assess how platform owners attain market dominance. We integrated our findings into a framework that depicts the interrelations between environmental factors and firm-level strategies as well as firm-level strategies and their effects for market dominance. The framework conceptualizes platform dominance to help a) attain it from a platform owner perspective, b) cope with it from a competitive perspective, and c) regulate it from a policy perspective. We propose three avenues for future research: (1) the role of national factors in attaining dominance; (2) factors enabling platforms to sustain dominance; and (3) strategies to dethrone dominant platforms

BREEDING GROUNDS OF DIGITAL PLATFORMS: EXPLORING THE SOURCES OF AMERICAN PLATFORM DOMINATION, CHINA’S PLATFORM SELF-SUFFICIENCY, AND EUROPE’S PLATFORM GAP

EU firms are largely dominated by American platforms in online consumer-facing markets as well as cloud computing services and are likely to face domination in further markets. In contrast, China has mainly escaped American domination and established a self-sufficient platform economy. This situation provides the opportunity to move beyond research on firm-level strategies of platform competitiveness and to assess national factors that foster the emergence and growth of digital platforms. Understanding different platform breeding grounds is essential to guide EU regulators toward a selfsufficient European platform economy and to help them protect EU firms from the risk of exploitation by dominant platforms. These insights are also important to develop a theory of platform regulation, especially as dominant platforms violate EU laws. To address this gap, this study builds upon 32 expert interviews across 7 EU countries and 19 industries. Our results indicate that in general, a fragmented market, risk-aversion, lack of local clusters, and lack of funding and, more specifically, late entrance, legacy systems, and historic dependence have led to the EU’s platform gap. We discuss why and how EU regulators should intervene and propose a regulatory strategy that establishes a selfsufficient EU platform economy

The Composition of the Arabidopsis RNA Polymerase II Transcript Elongation Complex Reveals the Interplay between Elongation and mRNA Processing Factors

Transcript elongation factors (TEFs) are a heterogeneous group of proteins that control the efficiency of transcript elongation of subsets of genes by RNA polymerase II (RNAPII) in the chromatin context. Using reciprocal tagging in combination with affinity purification and mass spectrometry, we demonstrate that in Arabidopsis thaliana, the TEFs SPT4/SPT5, SPT6, FACT, PAF1-C, and TFIIS copurified with each other and with elongating RNAPII, while P-TEFb was not among the interactors. Additionally, NAP1 histone chaperones, ATP-dependent chromatin remodeling factors, and some histone-modifying enzymes including Elongator were repeatedly found associated with TEFs. Analysis of double mutant plants defective in different combinations of TEFs revealed genetic interactions between genes encoding subunits of PAF1-C, FACT, and TFIIS, resulting in synergistic/epistatic effects on plant growth/development. Analysis of subnuclear localization, gene expression, and chromatin association did not provide evidence for an involvement of the TEFs in transcription by RNAPI (or RNAPIII). Proteomics analyses also revealed multiple interactions between the transcript elongation complex and factors involved in mRNA splicing and polyadenylation, including an association of PAF1-C with the polyadenylation factor CstF. Therefore, the RNAPII transcript elongation complex represents a platform for interactions among different TEFs, as well as for coordinating ongoing transcription with mRNA processing

Phosphorylation of the FACT histone chaperone subunit SPT16 affects chromatin at RNA polymerase II transcriptional start sites in Arabidopsis

The heterodimeric histone chaperone FACT, consisting of SSRP1 and SPT16, contributes to dynamic nucleosome rearrangements during various DNA-dependent processes including transcription. In search of post-translational modifications that may regulate the activity of FACT, SSRP1 and SPT16 were isolated from Arabidopsis cells and analysed by mass spectrometry. Four acetylated lysine residues could be mapped within the basic C-terminal region of SSRP1, while three phosphorylated serine/threonine residues were identified in the acidic C-terminal region of SPT16. Mutational analysis of the SSRP1 acetylation sites revealed only mild effects. However, phosphorylation of SPT16 that is catalysed by protein kinase CK2, modulates histone interactions. A non-phosphorylatable version of SPT16 displayed reduced histone binding and proved inactive in complementing the growth and developmental phenotypes of spt16 mutant plants. In plants expressing the non-phosphorylatable SPT16 version we detected at a subset of genes enrichment of histone H3 directly upstream of RNA polymerase II transcriptional start sites (TSSs) in a region that usually is nucleosome-depleted. This suggests that some genes require phosphorylation of the SPT16 acidic region for establishing the correct nucleosome occupancy at the TSS of active genes

Hypereosinophilic syndrome: a multicenter, retrospective analysis of clinical characteristics and response to therapy.

BACKGROUND: Hypereosinophilic syndrome (HES) is a heterogeneous group of rare disorders defined by persistent blood eosinophilia > or =1.5 x 10(9)/L, absence of a secondary cause, and evidence of eosinophil-associated pathology. With the exception of a recent multicenter trial of mepolizumab (anti-IL-5 mAb), published therapeutic experience has been restricted to case reports and small case series. OBJECTIVE: The purpose of the study was to collect and summarize baseline demographic, clinical, and laboratory characteristics in a large, diverse cohort of patients with HES and to review responses to treatment with conventional and novel therapies. METHODS: Clinical and laboratory data from 188 patients with HES, seen between January 2001 and December 2006 at 11 institutions in the United States and Europe, were collected retrospectively by chart review. RESULTS: Eighteen of 161 patients (11%) tested were Fip1-like 1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRA) mutation-positive, and 29 of 168 patients tested (17%) had a demonstrable aberrant or clonal T-cell population. Corticosteroid monotherapy induced complete or partial responses at 1 month in 85% (120/141) of patients with most remaining on maintenance doses (median, 10 mg prednisone equivalent daily for 2 months to 20 years). Hydroxyurea and IFN-alpha (used in 64 and 46 patients, respectively) were also effective, but their use was limited by toxicity. Imatinib (used in 68 patients) was more effective in patients with the FIP1L1-PDGFRA mutation (88%) than in those without (23%; P < .001). CONCLUSION: This study, the largest clinical analysis of patients with HES to date, not only provides useful information for clinicians but also should stimulate prospective trials to optimize treatment of HES.Journal ArticleMulticenter StudyResearch Support, N.I.H. ExtramuralResearch Support, N.I.H. IntramuralResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe