The overall objective of this study was to examine the links between teacher–student relationship quality and student engagement, delimited to affective and behavioural engagement. We used a sequential explanatory mixed methods research approach that consisted of a quantitative phase, in which survey data were collected and analysed within a short-term longitudinal design, followed by a qualitative phase, in which focus group interviews and constructed grounded theory analysis were conducted. Participants included 234 students from two Swedish compulsory schools in the quantitative phase, and 120 in the qualitative phase. The quantitative findings revealed that teacher–student relationship quality predicted student engagement one year later, even when controlling for sex, age, and prior student engagement. The longitudinal association between teacher–student relationship quality and student engagement was unidirectional. The qualitative findings reported students’ own perspectives on what they considered to be a good teacher and their ideas of how their teachers and classroom setting influence their affective and behavioural engagement at school. Two significant categories emerged: ‘teacher being’ and ‘teacher doing’.

Epigenetic regulation serves as the basis for stem cell differentiation into distinct cell types, but it is unclear how global epigenetic changes are regulated during this process. Here, we tested the hypothesis that global chromatin organization affects the lineage potential of stem cells and that manipulation of chromatin dynamics influences stem cell function. Using nuclease sensitivity assays, we found a progressive decrease in chromatin digestion among pluripotent embryonic stem cells (ESCs), multipotent hematopoietic stem cells (HSCs), and mature hematopoietic cells. Quantitative high-resolution microscopy revealed that ESCs contain significantly more euchromatin than HSCs, with a further reduction in mature cells. Increased cellular maturation also led to heterochromatin localization to the nuclear periphery. Functionally, prevention of heterochromatin formation by inhibition of the histone methyltransferase G9A resulted in delayed HSC differentiation. Our results demonstrate global chromatin rearrangements during stem cell differentiation and that heterochromatin formation by H3K9 methylation regulates HSC differentiation.

Hematopoietic stem cells (HSC) are rare, multipotent cells capable of generating all specialized cells of the blood system. Appropriate regulation of HSC quiescence is thought to be crucial to maintain their lifelong function; however, the molecular pathways controlling stem cell quiescence remain poorly characterized. Likewise, the molecular events driving leukemogenesis remain elusive. In this study, we compare the gene expression profiles of steady-state bone marrow HSC to non-self-renewing multipotent progenitors; to HSC treated with mobilizing drugs that expand the HSC pool and induce egress from the marrow; and to leukemic HSC in a mouse model of chronic myelogenous leukemia. By intersecting the resulting lists of differentially regulated genes we identify a subset of molecules that are downregulated in all three circumstances, and thus may be particularly important for the maintenance and function of normal, quiescent HSC. These results identify potential key regulators of HSC and give insights into the clinically important processes of HSC mobilization for transplantation and leukemic development from cancer stem cells.