Molecular investigation of the tandem Tudor domain and plant homeodomain histone binding domains of the epigenetic regulator UHRF2

Ubiquitin-like containing PHD and ring finger (UHRF)1 and UHRF2 are multidomain epigenetic proteins that play a critical role in bridging crosstalk between histone modifications and DNA methylation. Both proteins contain two histone reader domains, called tandem Tudor domain (TTD) and plant homeodomain (PHD), which read the modification status on histone H3 to regulate DNA methylation and gene expression. To shed light on the mechanism of histone binding by UHRF2, we have undergone a detailed molecular investigation with the TTD, PHD and TTD-PHD domains and compared the binding activity to its UHRF1 counterpart. We found that unlike UHRF1 where the PHD is the primary binding contributor, the TTD of UHRF2 has modestly higher affinity toward the H3 tail, while the PHD has a weaker binding interaction. We also demonstrated that like UHRF1, the aromatic amino acids within the TTD are important for binding to H3K9me3 and a conserved aspartic acid within the PHD forms an ionic interaction with R2 of H3. However, while the aromatic amino acids in the TTD of UHRF1 contribute to selectivity, the analogous residues in UHRF2 contribute to both selectivity and affinity. We also discovered that the PHD of UHRF2 contains a distinct asparagine in the H3R2 binding pocket that lowers the binding affinity of the PHD by reducing a potential electrostatic interaction with the H3 tail. Furthermore, we demonstrate the PHD and TTD of UHRF2 cooperate to interact with the H3 tail and that dual domain engagement with the H3 tail relies on specific amino acids. Lastly, our data indicate that the unique stretch region in the TTD of UHRF2 can decrease the melting temperature of the TTD-PHD and represents a disordered region. Thus, these subtle but important mechanistic differences are potential avenues for selectively targeting the histone binding interactions of UHRF1 and UHRF2 with small molecules.

Motivational interviewing to improve postabortion contraceptive uptake by young women: development and feasibility of a counseling intervention

OBJECTIVE

The objective was to develop and test a postabortal contraception counseling intervention using motivational interviewing (MI) and to determine the feasibility, impact and patient acceptability of the intervention when integrated into an urban academic abortion clinic.

STUDY DESIGN

A single-session postabortal contraception counseling intervention for young women aged 15-24 years incorporating principles, skills and style of MI was developed. Medical and social work professionals were trained to deliver the intervention, their competency was assessed, and the intervention was integrated into the clinical setting. Feasibility was determined by assessing ability to approach and recruit participants, ability to complete the full intervention without interruption and participant satisfaction with the counseling.

RESULTS

We approached 90% of eligible patients and 71% agreed to participate (n=20). All participants received the full counseling intervention. The median duration of the intervention was 29 min. Immediately after the intervention and at the 1-month follow-up contact, 95% and 77% of participants reported that the session was helpful, respectively.

CONCLUSIONS

MI counseling can be tailored to the abortion setting. It is feasible to train professionals to use MI principles, skills and style and to implement an MI-based contraception counseling intervention in an urban academic abortion clinic. The sessions are acceptable to participants.

IMPLICATIONS

The use of motivational interviewing in contraception counseling may be an appropriate and effective strategy for increasing use of contraception after abortion. This study demonstrates that this patient-centered, directive and collaborative approach can be developed into a counseling intervention that can be integrated into an abortion clinic.

Immunomodulatory molecules are released from the first trimester and term placenta via exosomes

The semiallogenic fetus is tolerated by the maternal immune system through control of innate and adaptive immune responses. Trophoblast cells secrete nanometer scale membranous particles called exosomes, which have been implicated in modulation of the local and systemic maternal immune system. Here we investigate the possibility that exosomes secreted from the first trimester and term placenta carry HLA-G and B7 family immunomodulators. Confocal microscopy of placental sections revealed intracellular co-localization of B7-H1 with CD63, suggesting that B7-H1 associates with subcellular vesicles that give rise to exosomes. First trimester and term placental explants were then cultured for 24 h. B7H-1 (CD274), B7-H3 (CD276) and HLA-G5 were abundant in pelleted supernatants of these cultures that contained microparticles and exosomes; the latter, however, was observed only in first trimester pellets and was nearly undetectable in term explant-derived pellets. Further purification of exosomes by sucrose density fractionation confirmed the association of these proteins specifically with exosomes. Finally, culture of purified trophoblast cells in the presence or absence of EGF suggested that despite the absence of HLA-G5 association with term explant-derived exosomes, it is present in exosomes secreted from mononuclear cytotrophoblast cells. Further, differentiation of cytotrophoblast cells reduced the presence of HLA-G5 in secreted exosomes. Together, the results suggest that the immunomodulatory proteins HLA-G5, B7-H1 and B7-H3, are secreted from early and term placenta, and have important implications in the mechanisms by which trophoblast immunomodulators modify the maternal immunological environment.

Parental age effects on cortical morphology in offspring

The age at which a parent has a child impacts the child's cognition and risk for mental illness. It appears that this risk is curvilinear, with both age extremes associated with lower intelligence and increased prevalence of some neuropsychiatric disorders. Little is known of the neural mechanisms underpinning this phenomenon. We extracted lobar volumes, surface areas, and cortical thickness from 489 neuroanatomic magnetic resonance images acquired on 171 youth. Using linear mixed model regression, we determined the association between parental age and offspring's neuroanatomy, adjusting for offspring's age, sex, intelligence, and parental socioeconomic class. For gray matter volumes, quadratic paternal and maternal age terms contributed significantly (maternal quadratic age effect: t = -2.2, P = 0.03; paternal quadratic age effect: t = -2.4, P = 0.02) delineating an inverted "U" relationship between parental age and gray matter volume. Cortical volume increased with both advancing paternal and maternal age until around the early 30s after which it fell. Paternal age effects were more pronounced on cortical surface area, whereas maternal age impacted more on cortical thickness. There were no significant effects of parental age on white matter volumes. These parental age effects on cerebral morphology may form part of the link between parental age extremes and suboptimal neurocognitive outcomes.

A radiographic survey of dental anomalies in Black pediatric patients

During seemingly routine check-ups, the dental practitioner must be ever aware of "quiescent" abnormalities or irregularities. Knowledge of special problems occurring within a certain patient population is of great value to the practitioner when evaluating the individual patient. Numerous studies have been conducted evaluating the pediatric Caucasian population; however, no comparable studies for the Black pediatric population have been done. This study sought to establish prevalence rates for the Black pediatric population with regards to the following anomalies: congenitally missing teeth, supernumerary teeth, dens in dente, odontomas, dentinogenesis imperfecta, gemination, fusion and concrescence. The radiographs (panographs mandatory), history forms and treatment progress records of 2,267 children (1,136 males and 1,131 females) were analyzed. Radiographs of poor quality were eliminated and attempts were made to include only children of Black American heritage. Prevalence rates established for a predominantly Black pediatric population were: 4.4%, congenitally missing teeth; 1.49%, supernumerary teeth; 0.26%, dentinogenesis imperfecta (Brandywine type); 0.44%, odontomas; 0.22%, gemination; and 0.12%, fusion. Evidence of dens in dente was found in only one erupted supernumerary maxillary paralateral, and the detection of only one case of concrescence occurred; both have prevalence rates of 0.04%. No other study has produced such a high rate of dentinogenesis imperfecta (.26%), except that conducted within the tri-racial group itself. In addition, if assumptions are to be made from this investigation for the general population, supernumeraries and odontomas may be present significantly more often in the Black than Caucasian pediatric population.

Importance of filter structure for the trans-membrane migration studies of sperm motility

Sperm migration through polycarbonate and nylon membrane filters was studied by the trans-membrane migration ratio method. Sperm crossed the former filters but not the latter because of the greater pore length and complexity of the relatively thick nylon membrane. Adhesion of spermatozoa to the nylon structure was also observed. Using the polycarbonate filter we were able to correlate trans-membrane migration with conventional motility and measure the effects of drugs on sperm motility.