Cohesin interaction with centromeric minichromosomes shows a multi-complex rod-shaped structure.

Cohesin is the protein complex responsible for maintaining sister chromatid cohesion. Cohesin interacts with centromeres and specific loci along chromosome arms known as Chromosome Attachment Regions (CARs). The cohesin holocomplex contains four subunits. Two of them, Smc1p (Structural maintenance of chromosome 1 protein) and Smc3p, are long coiled-coil proteins, which heterodimerize with each other at one end. They are joined together at the other end by a third subunit, Scc1p, which also binds to the fourth subunit, Scc3p. How cohesin interacts with chromosomes is not known, although several models have been proposed, in part on the basis of in vitro assembly of purified cohesin proteins. To be able to observe in vivo cohesin-chromatin interactions, we have modified a Minichromosome Affinity Purification (MAP) method to isolate a CAR-containing centromeric minichromosome attached to in vivo assembled cohesin. Transmission Electron Microscopy (TEM) analysis of these minichromosomes suggests that cohesin assumes a rod shape and interacts with replicated minichromosome at one end of that rod. Additionally, our data implies that more than one cohesin molecule interacts with each pair of replicated minichromsomes. These molecules seem to be packed into a single thick rod, suggesting that the Smc1p and Smc3p subunits may interact extensively

Entosis Is Induced by Glucose Starvation

Entosis is a mechanism of cell death that involves neighbor cell ingestion. This process occurs in cancers and promotes a form of cell competition, where winner cells engulf and kill losers. Entosis is driven by a mechanical differential that allows softer cells to eliminate stiffer cells. While this process can be induced by matrix detachment, whether other stressors can activate entosis is unknown. Here, we find that entosis is induced in adherent cells by glucose withdrawal. Glucose withdrawal leads to a bimodal distribution of cells based on their deformability, where stiffer cells appear in a manner requiring the energy-sensing AMP-activated protein kinase (AMPK). We show that loser cells with high levels of AMPK activity are eliminated by winners through entosis, which supports winner cell proliferation under nutrient-deprived conditions. Our findings demonstrate that entosis serves as a cellular response to metabolic stress that enables nutrient recovery through neighbor cell ingestion

Neonatal Hemochromatosis: Systematic Review of Prenatal Ultrasound Findings—Is There a Place for MRI in the Diagnostic Process?

Neonatal hemochromatosis (NH) is an uncommon, severe disorder that results in fetal loss or neonatal death due to liver failure. NH is currently regarded as the phenotypic expression of gestational alloimmune liver disease (GALD). The diagnosis of NH-GALD is rarely prenatally established. In addition to providing a systematic review of the prenatal features that are identifiable using ultrasound (US) and MRI, we suggest a prenatal diagnosis algorithm for use in suspected NH during the first affected pregnancy. From a total of 586 database entries identified in PubMed, Google Scholar, and ResearchGate, we selected 18 studies published from 1993 to 2021 that reported maternal medical and obstetric history, prenatal ultrasound findings, and postpartum outcomes. We investigated the ultrasound and MRI features of these studies, along with the outcome due to this condition. A total of 74 cases were identified. The main reported prenatal US finding was fetal growth restriction (FGR) (33%), followed by oligohydramnios (13%) and hydrops fetalis (13%), with 13% cases described as uneventful. Other rare prenatal findings were fetal anemia, ascites, and abnormal fetal liver and spleen. Most pregnancies ended with fetal/perinatal death or therapeutic interruption of pregnancy. Favorable evolution with treatment (ensanguine transfusion and intravenous immunoglobulin (IVIG)) was reported for only 7% of fetuses. Using T2-weighted MRI, fetal extrahepatic siderosis confirmed prenatally in two cases and postnatally in 11 cases. IVIG treatment throughout subsequent pregnancies was found to significantly improve fetal prognosis. MRI should be indicated in selected cases of oligohydramnios, fetal hydrops, fetal hepatomegaly, ascites, or unexplained FGR or anemia after ruling out all other more frequently encountered conditions. MRI can be used to detect iron overload in the liver and extrahepatic siderosis

The Joint Role of Thyroid Function and Iodine Status on Risk of Preterm Birth and Small for Gestational Age: A Population-Based Nested Case-Control Study of Finnish Women

Normal maternal thyroid function during pregnancy is essential for fetal development and depends upon an adequate supply of iodine. Little is known about how iodine status is associated with preterm birth and small for gestational age (SGA) in mildly iodine insufficient populations. Our objective was to evaluate associations of early pregnancy serum iodine, thyroglobulin (Tg), and thyroid-stimulating hormone (TSH) with odds of preterm birth and SGA in a prospective, population-based, nested case-control study from all births in Finland (2012–2013). Cases of preterm birth (n = 208) and SGA (n = 209) were randomly chosen from among all singleton births. Controls were randomly chosen from among singleton births that were not preterm (n = 242) or SGA (n = 241) infants during the same time period. Women provided blood samples at 10–14 weeks’ gestation for serum iodide, Tg and TSH measurement. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for preterm birth and SGA. Each log-unit increase in serum iodide was associated with higher odds of preterm birth (adjusted OR = 1.19, 95% CI = 1.02–1.40), but was not associated with SGA (adjusted OR = 1.01, 95% CI = 0.86–1.18). Tg was not associated with preterm birth (OR per 1 log-unit increase = 0.87, 95% CI = 0.73–1.05), but was inversely associated with SGA (OR per log-unit increase = 0.78, 95% CI = 0.65–0.94). Neither high nor low TSH (versus normal) were associated with either outcome. These findings suggest that among Finnish women, iodine status is not related to SGA, but higher serum iodide may be positively associated with preterm birth