Antenatal and neonatal exposure to SARS-CoV-2 and children's development: a systematic review and meta-analysis.

OBJECTIVES: To conduct a systematic review of the impact of antenatal and neonatal exposure to SARS-CoV-2 on developmental outcomes in preterm and term-born infants. METHODS: We searched Embase, Emcare, MEDLINE, PsycINFO, Web of Science and grey literature on May 27, 2022 and updated on May 8, 2023. Studies defining exposure with a positive SARS-CoV-2 protein or genetic material, used a contemporaneous non-exposed cohort, and reported developmental outcomes up to 2 years of age were included. RESULTS: Four out of 828 screened studies were included. Meta-analysis included 815 infants screened for developmental delay (n = 306 exposed; n = 509 non-exposed) between 3- and 11-months of age. Among term-born infants, we did not find an increased risk of delay in communication (odd's ratio: 0.73 (95% CI: 0.24-2.24)), gross motor (1.50 (0.62, 3.62)), fine motor (2.90 (0.58, 14.43)), problem-solving (1.19 (0.54, 2.66)) or personal-social development (1.93 (0.78, 4.75)) in exposed infants. The number of preterm-born infants in the exposed (n = 37) and comparison cohorts (n = 41) were too few to report meaningful comparisons. CONCLUSION: Evidence regarding the potential impact of antenatal or neonatal exposure to SARS-CoV-2 infection on developmental outcomes in early infancy is limited and inconsistent. Larger cohorts with outcomes beyond the first year of life are needed. IMPACT: The current evidence examining associations between SARS-CoV-2 exposure during the neonatal period and developmental outcomes in infancy is limited by there being few studies with extremely small sample sizes. Based on sparse data there was no consistent association between antenatal or neonatal exposure to SARS-CoV-2 infection and an adverse impact on developmental outcomes below 12 months of age for babies born preterm or at term. This study highlights that larger cohorts with outcomes assessed beyond the first year are needed to determine the potential longer-term impact of SARS-CoV-2 infection exposure on child development.

Claspin is phosphorylated in the Chk1-binding domain by a kinase distinct from Chk1.

Chk1 protein kinase plays a critical role in checkpoints that restrict progression through the cell cycle if DNA replication has not been completed or DNA damage has been sustained. ATR-dependent activation of Chk1 is mediated by Claspin. Phosphorylation of Claspin at two sites (Thr916 and Ser945 in humans) in response to DNA replication arrest or DNA damage recruits Chk1 to Claspin. Chk1 is subsequently phosphorylated by ATR and fully activated to control cell cycle progression. We show that ablation of Chk1 by siRNA in human cells or its genetic deletion in chicken DT40 cells does not prevent phosphorylation of Claspin at Thr916 (Ser911 in chicken). Chk1, however, does play other roles, possibly indirect, in the phosphorylation of Claspin and its induction. These results demonstrate that phosphorylation of Claspin within the Chk1-binding domain is catalysed by an ATR-dependent kinase distinct from Chk1.

BRCA1 is a histone-H2A-specific ubiquitin ligase.

The RING domain proteins BRCA1 and BARD1 comprise a heterodimeric ubiquitin (E3) ligase that is required for the accumulation of ubiquitin conjugates at sites of DNA damage and for silencing at DNA satellite repeat regions. Despite its links to chromatin, the substrate and underlying function of the BRCA1/BARD1 ubiquitin ligase remain unclear. Here, we show that BRCA1/BARD1 specifically ubiquitylates histone H2A in its C-terminal tail on lysines 127 and 129 in vitro and in vivo. The specificity for K127-129 is acquired only when H2A is within a nucleosomal context. Moreover, site-specific targeting of the BRCA1/BARD1 RING domains to chromatin is sufficient for H2Aub foci formation in vivo. Our data establish BRCA1/BARD1 as a histone-H2A-specific E3 ligase, helping to explain its localization and activities on chromatin in cells.