<i>Melav2</i>, an <i>elav</i>-like gene, is essential for spermatid differentiation in the flatworm <i>Macrostomum lignano</i>

BackgroundFailure of sperm differentiation is one of the major causes of male sterility. During spermiogenesis, spermatids undergo a complex metamorphosis, including chromatin condensation and cell elongation. Although the resulting sperm morphology and property can vary depending on the species, these processes are fundamental in many organisms. Studying genes involved in such processes can thus provide important information for a better understanding of spermatogenesis, which might be universally applied to many other organisms.ResultsIn a screen for genes that have gonad-specific expression we isolated an elav-like gene, melav2, from Macrostomum lignano, containing the three RNA recognition motifs characteristic of elav-like genes. We found that melav2 mRNA was expressed exclusively in the testis, as opposed to the known elav genes, which are expressed in the nervous system. The RNAi phenotype of melav2 was characterized by an aberrant spermatid morphology, where sperm elongation often failed, and an empty seminal vesicle. Melav2 RNAi treated worms were thus male-sterile. Further analysis revealed that in melav2 RNAi treated worms precocious chromatin condensation occurred during spermatid differentiation, resulting in an abnormally tightly condensed chromatin and large vacuoles in round spermatids. In addition, immunostaining using an early-spermatid specific antibody revealed that melav2 RNAi treated worms had a larger amount of signal positive cells, suggesting that many cells failed the transition from early spermatid stage.ConclusionWe characterize a new function for elav-like genes, showing that melav2 plays a crucial role during spermatid differentiation, especially in the regulation of chromatin condensation and/or cell elongation

Co-navigating the Complexities of School Reform: The Establishment and On-going Maintenance of Relational Trust in School Reform Efforts

The purpose of this research was to examine the ways in which the principal and literacy coach collectively developed and maintained relational trust in order to establish school literacy reform efforts. Drawing from a larger set of data, we employed qualitative methods to explore interviews and surveys from the principals and literacy coaches at two different schools who were able to implement literacy reform for several consecutive years. The relational trust established between the coach and principal enabled them to co-navigate issues that might have otherwise impeded literacy reform efforts in their school. Acting together, the principal and the coach were able to communicate a common vision for literacy reform, which resulted in increased implementation of the reform framework in their schools

Experimental and theoretical investigations of a rectangular grating structure for low-voltage traveling wave tube amplifiers

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UniPROBE, update 2011: expanded content and search tools in the online database of protein-binding microarray data on protein–DNA interactions

The Universal PBM Resource for Oligonucleotide-Binding Evaluation (UniPROBE) database is a centralized repository of information on the DNA-binding preferences of proteins as determined by universal protein-binding microarray (PBM) technology. Each entry for a protein (or protein complex) in UniPROBE provides the quantitative preferences for all possible nucleotide sequence variants (‘words’) of length k (‘k-mers’), as well as position weight matrix (PWM) and graphical sequence logo representations of the k-mer data. In this update, we describe >130% expansion of the database content, incorporation of a protein BLAST (blastp) tool for finding protein sequence matches in UniPROBE, the introduction of UniPROBE accession numbers and additional database enhancements. The UniPROBE database is available at http://uniprobe.org.National Institutes of Health (U.S.) (grant number R01 HG003985

UniPROBE, update 2011: expanded content and search tools in the online database of protein-binding microarray data on protein–DNA interactions

The Universal PBM Resource for Oligonucleotide-Binding Evaluation (UniPROBE) database is a centralized repository of information on the DNA-binding preferences of proteins as determined by universal protein-binding microarray (PBM) technology. Each entry for a protein (or protein complex) in UniPROBE provides the quantitative preferences for all possible nucleotide sequence variants (‘words’) of length k (‘k-mers’), as well as position weight matrix (PWM) and graphical sequence logo representations of the k-mer data. In this update, we describe >130% expansion of the database content, incorporation of a protein BLAST (blastp) tool for finding protein sequence matches in UniPROBE, the introduction of UniPROBE accession numbers and additional database enhancements. The UniPROBE database is available at http://uniprobe.org.National Institutes of Health (U.S.) (grant number R01 HG003985

Drosophila DNA polymerase theta utilizes both helicase-like and polymerase domains during microhomology-mediated end joining and interstrand crosslink repair

Double strand breaks (DSBs) and interstrand crosslinks (ICLs) are toxic DNA lesions that can be repaired through multiple pathways, some of which involve shared proteins. One of these proteins, DNA Polymerase θ (Pol θ), coordinates a mutagenic DSB repair pathway named microhomology-mediated end joining (MMEJ) and is also a critical component for bypass or repair of ICLs in several organisms. Pol θ contains both polymerase and helicase-like domains that are tethered by an unstructured central region. While the role of the polymerase domain in promoting MMEJ has been studied extensively both in vitro and in vivo, a function for the helicase-like domain, which possesses DNA-dependent ATPase activity, remains unclear. Here, we utilize genetic and biochemical analyses to examine the roles of the helicase-like and polymerase domains of Drosophila Pol θ. We demonstrate an absolute requirement for both polymerase and ATPase activities during ICL repair in vivo. However, similar to mammalian systems, polymerase activity, but not ATPase activity, is required for ionizing radiation-induced DSB repair. Using a site-specific break repair assay, we show that overall end-joining efficiency is not affected in ATPase-dead mutants, but there is a significant decrease in templated insertion events. In vitro, Pol θ can efficiently bypass a model unhooked nitrogen mustard crosslink and promote DNA synthesis following microhomology annealing, although ATPase activity is not required for these functions. Together, our data illustrate the functional importance of the helicase-like domain of Pol θ and suggest that its tethering to the polymerase domain is important for its multiple functions in DNA repair and damage tolerance

Parenting the Premature Infant: Potential Iatrogenesis from the Neonatal Intensive Care Experience

(1) Developmental outcomes of premature infants are associated with the quality of the home environment and the level of parenting skills the family possesses. Successful development of the parenting role may be negatively influenced by the Neonatal Intensive Care Unit (NICU) environment and nursing practices. Identification of interventions that promote the development of parenting skills in the NICU can potentially improve developmental outcomes for premature infants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73814/1/j.1524-475X.1996.00046.x.pd

Challenges of caring for children with mental disorders: Experiences and views of caregivers attending the outpatient clinic at Muhimbili National Hospital, Dar es Salaam - Tanzania

It is estimated that world-wide up to 20 % of children suffer from debilitating mental illness. Mental disorders that pose a significant concern include learning disorders, hyperkinetic disorders (ADHD), depression, psychosis, pervasive development disorders, attachment disorders, anxiety disorders, conduct disorder, substance abuse and eating disorders. Living with such children can be very stressful for caregivers in the family. Therefore, determination of challenges of living with these children is important in the process of finding ways to help or support caregivers to provide proper care for their children. The purpose of this study was to explore the psychological and emotional, social, and economic challenges that parents or guardians experience when caring for mentally ill children and what they do to address or deal with them. A qualitative study design using in-depth interviews and focus group discussions was applied. The study was conducted at the psychiatric unit of Muhimbili National Hospital in Tanzania. Two focus groups discussions (FGDs) and 8 in-depth interviews were conducted with caregivers who attended the psychiatric clinic with their children. Data analysis was done using content analysis. The study revealed psychological and emotional, social, and economic challenges caregivers endure while living with mentally ill children. Psychological and emotional challenges included being stressed by caring tasks and having worries about the present and future life of their children. They had feelings of sadness, and inner pain or bitterness due to the disturbing behaviour of the children. They also experienced some communication problems with their children due to their inability to talk. Social challenges were inadequate social services for their children, stigma, burden of caring task, lack of public awareness of mental illness, lack of social support, and problems with social life. The economic challenges were poverty, child care interfering with various income generating activities in the family, and extra expenses associated with the child's illness. Caregivers of mentally ill children experience various psychological and emotional, social, and economic challenges. Professional assistance, public awareness of mental illnesses in children, social support by the government, private sector, and non-governmental organizations (NGOs) are important in addressing these challenges

FANCI and FANCD2 have common as well as independent functions during the cellular replication stress response

Fanconi anemia (FA) is an inherited cancer predisposition syndrome characterized by cellular hypersensitivity to DNA interstrand crosslinks (ICLs). To repair these lesions, the FA proteins act in a linear hierarchy: following ICL detection on chromatin, the FA core complex monoubiquitinates and recruits the central FANCI and FANCD2 proteins that subsequently coordinate ICL removal and repair of the ensuing DNA double-stranded break by homology-dependent repair (HDR). FANCD2 also functions during the replication stress response by mediating the restart of temporarily stalled replication forks thereby suppressing the firing of new replication origins. To address if FANCI is also involved in these FANCD2-dependent mechanisms, we generated isogenic FANCI-, FANCD2- and FANCI:FANCD2 double-null cells. We show that FANCI and FANCD2 are partially independent regarding their protein stability, nuclear localization and chromatin recruitment and contribute independently to cellular proliferation. Simultaneously, FANCD2-but not FANCI-plays a major role in HDR-mediated replication restart and in suppressing new origin firing. Consistent with this observation, deficiencies in HDR-mediated DNA DSB repair can be overcome by stabilizing RAD51 filament formation in cells lacking functional FANCD2. We propose that FANCI and FANCD2 have partially non-overlapping and possibly even opposing roles during the replication stress response