Oscillating autonomy: a grounded theory study of women's experiences of COVID-19 infection during pregnancy, labour and birth, and the early postnatal period.

BACKGROUND: Testing positive for COVID-19 was associated with higher rates of detrimental psycho-social and physical health outcomes. The COVID-19 pandemic caused unprecedented disruption to everyday life. This included major reconfiguration of maternal, child, and perinatal mental health and care services and provision. This study aimed to investigate the experiences of those who tested positive for COVID-19 during pregnancy, labour and birth, or the early postnatal period. METHODS: National on-line recruitment from across the United Kingdom resulted in sixteen mothers being invited to qualitative semi-structured interviews to understand the experiences of mothers who had been infected by COVID-19 during pregnancy, labour and birth, or the early postnatal period. Interviews were conducted, recorded, and transcribed using video-conferencing software. A Grounded Theory approach was used to analyse the data gathered pertaining to women's experiences of their positive COVID-19 diagnosis during pregnancy, labour and birth, or the early postnatal period. RESULTS: The theory of 'Oscillating Autonomy - Losing and Seeking to Regain Control by Striving for Agency' was developed, comprising three main themes: 'Anxious Anticipation: The fear of infection was worse than COVID-19 itself'; 'Fluctuating Agency: What changed when COVID-19 took control'; and 'Reclaiming Control: Seeking reassurance during COVID-19 positivity'. Testing positive for COVID-19 whilst pregnant, during labour or birth, or in the early postnatal period was associated with a perceived loss of control. Those who were able to regain that control felt more secure in their situation. CONCLUSIONS: Support was paramount to manage increased vulnerability, as was reassurance achieved by information seeking and positive action including increased health monitoring and COVID-19 vaccination.

Long-term follow-up of fertility and pregnancy in autoimmune diseases after autologous haematopoietic stem cell transplantation.

Issues of fertility and pregnancy require special attention in the long-term care of patients with autoimmune diseases (AD), who are candidates for haematopoietic stem cell transplantation (HSCT). In this single-centre observational study, we report fertility status and pregnancy outcomes in 15 patients (11 female and 4 male) after immunoablation with cyclophosphamide, antithymocyte globulin and autologous CD34+-selected HSCT for severe, refractory AD. The median follow-up after HSCT was 12 years (range 2-16 years). Impaired fertility was observed in six patients (five females and one male) before HSCT based on sexual hormone measurements. Higher age and cumulative cyclophosphamide dosage before HSCT correlated with fertility impairment. Median serum level of follicle-stimulating hormone (FSH) was significantly higher in female patients at 1 year after HSCT compared to baseline values, but premature ovarian failure developed in only one patient. Four women had five pregnancies and six healthy offsprings during follow-up, and no miscarriages were observed. The mothers were in treatment-free remissions during conception. No peripartal flare of their AD occurred. Although AD patients undergoing HSCT are at risk of developing infertility, pre-HSCT treatment and patients' age seem to have higher impact on long-term fertility status than HSCT itself. HSCT offers the opportunity to conceive during treatment-free remissions with favourable pregnancy outcomes.

SM-Omics is an automated platform for high-throughput spatial multi-omics.

The spatial organization of cells and molecules plays a key role in tissue function in homeostasis and disease. Spatial transcriptomics has recently emerged as a key technique to capture and positionally barcode RNAs directly in tissues. Here, we advance the application of spatial transcriptomics at scale, by presenting Spatial Multi-Omics (SM-Omics) as a fully automated, high-throughput all-sequencing based platform for combined and spatially resolved transcriptomics and antibody-based protein measurements. SM-Omics uses DNA-barcoded antibodies, immunofluorescence or a combination thereof, to scale and combine spatial transcriptomics and spatial antibody-based multiplex protein detection. SM-Omics allows processing of up to 64 in situ spatial reactions or up to 96 sequencing-ready libraries, of high complexity, in a ~2 days process. We demonstrate SM-Omics in the mouse brain, spleen and colorectal cancer model, showing its broad utility as a high-throughput platform for spatial multi-omics.

Fertility Preserving Surgery Outcomes for Ovarian Malignancy: Data from a Tertiary Cancer Centre in Central London.

Fertility Sparing Surgery (FSS) appears to be a safe means of treating early-stage ovarian cancer based on relatively limited evidence. However, there is currently insufficient evidence to aid women in counselling about their potential fertility outcomes. The aim of this study was to assess the reproductive outcomes and prognosis of women who have undergone FSS for ovarian malignancy. Between 1 June 2008 and 1 June 2018, a retrospective review of a clinical database was conducted to identify all consecutive patients who underwent FSS in a central London gynaecological oncology centre. All patients with a histological diagnosis of ovarian malignancy (excluding borderline ovarian tumours) were eligible. All identified patients were then prospectively called into a follow up and asked to complete a questionnaire about their fertility outcomes. A total of 47 women underwent FSS; 36 were included in this study. The mean age was 30.3 years (95% Confidence Interval [CI]: 27.6 to 33.0 years). During the study period, 17/36 (47.2%) of the women had attempted to conceive following surgery, with a successful live birth rate of 52.9% (9/17). The mean time of recurrence was 125.3 months (95% CI: 106.5−144.1 months). The mean time to death was 139.5 months (95% CI: 124.3−154.8). The cancer grade, tumour stage and use of Assisted Reproductive Technology (ART) were the main factors significantly associated with the risk of recurrence and death. In conclusion, this study suggests that a large proportion of women will not attempt to conceive following FSS. For those who do attempt to conceive, the likelihood of achieving a live birth is high. However, careful counselling about the higher risk of recurrence and worse survival for women with high grade cancer, disease Stage > IA and potentially those who undergo ART is essential before contemplating FFS.

Organelle relationships in cultured 3T3-L1 preadipocytes.

In differentiating 3T3-L1 cells, lipid spheres, the endoplasmic reticulum (ER), microperoxisomes, and mitochondria form "constellations" that may reflect the interplay of lipid metabolizing enzymes in these organelles. ER cisternae are also situated very close to "rosettes,"plasmalemmal specializations found in mature adipocytes in vivo. As in hepatocytes and absorptive cells of the intestine, this spatial relationship of ER and plasmalemma suggests a role for rosettes in the uptake of exogenous lipid precursors. The morphological differentiation of 3T3-L1 preadipocytes includes the loss of "stress fibers" and the appearance of microfilament like structures that encase, in a complex manner, the cytosolic lipid spheres that appear during differentiation. Other features described for the first time in 3T3-L1 preadipocytes include: (a) the presence of an extensive acid phosphatase (AcPase) positive GERL from which coated vesicles apparently arise (these coated vesicles display AcPase activity and are much smaller and far more numerous than the coated vesicles that seem to arise from the plasmalemmal coated pits); (b) the abundance of AcPase-positive autophagic vacuoles; and (c) a high level of alpha-naphthyl-acetate-esterase activity which, by light microscopy cytochemistry, appears to be localized in the cytosol.

Biochemical analysis of mutants of a macrophage cell line resistant to the growth-inhibitory activity of interferon.

While a multiplicity of cellular and biochemical effects are mediated by interferons on cultured cells, the mechanisms involved in the direct growth-inhibitory activity of interferons remain problematic. We have previously found that variants in cAMP metabolism in a macrophage cell line, J774.2, were at least 50-fold less sensitive to the growth inhibitory activity of interferons (IFN) than the parental clone. To test the hypothesis that cAMP mediates the growth inhibition produced by IFN in these cells, interferon-resistant variants were selected and characterized with respect to cAMP synthesis and function. Approximately one-third of the IFN-resistant clones were found to be resistant to growth inhibition produced by cholera toxin, but not 8Br-cAMP. IFN was fully able to protect all of the interferon-resistant/choleratoxin-resistant (IFNr/CTr) clones against infection by vesicular stomatitis virus and markedly stimulated 2', 5'-oligodenylate synthetase activity. These IFNr/CTr variants were shown to have a defect in adenylate cyclase. The remaining IFN-resistant clones were fully susceptible to the growth-inhibitory effects of cholera toxin because their basal and stimulated adenylate cyclase activity is similar to that of the parental clone. IFN failed to protect these IFNr/choleratoxin sensitive clones against infection by vesicular stomatitis virus and failed to stimulate 2', 5-oligodenylate synthetase, suggesting that they have defective or deficient IFN receptors. In addition, IFN failed to increase intracellular cAMP levels in both IFNr/CTr and IFNr/choleratoxin sensitive clones. These results provide firm genetic and biochemical evidence that the growth inhibitory effects of IFN on this cell line are mediated by cAMP.

Trifluoperazine inhibits phagocytosis in a macrophagelike cultured cell line.

Trifluoperazine, a drug that binds to Ca2+-calmodulin and inhibits its interaction with other proteins, was found to inhibit growth and phagocytosis in a macrophagelike cell line, J774.16. Both effects were reversible and occurred at the same concentrations of drug (25--50 microM) that inhibited the activation of cyclic nucleotide phosphodiesterase by calmodulin in vitro. Fc-mediated phagocytosis was also depressed by W-7, a sulfonamide derivative that inhibits the activity of Ca2+-calmodulin. In contrast, taxol, a drug that stabilizes cellular microtubules, had no effect on Fc-mediated phagocytosis although it inhibited cell growth at nanomolar concentrations. The inhibitory effects of trifluoperazine and W-7 on phagocytosis suggest that calmodulin may be involved in this complex cellular function.

After insulin binds.

Three recent advances pertinent to the mechanism of insulin action include (i) the discovery that the insulin receptor is an insulin-dependent protein tyrosine kinase, functionally related to certain growth factor receptors and oncogene-encoded proteins, (ii) the molecular cloning of the insulin proreceptor complementary DNA, and (iii) evidence that the protein tyrosine kinase activity of the receptor is essential for insulin action. Efforts are now focusing on the physiological substrates for the receptor kinase. Experience to date suggests that they will be rare proteins whose phosphorylation in intact cells may be transient. The advantages of attempting to dissect the initial biochemical pathway of insulin action include the wealth of information about the metabolic consequences of insulin action and the potential for genetic analysis in Drosophila and in man.

Transformation of rat fibroblasts by FSV rapidly increases glucose transporter gene transcription.

Elevation of glucose transport is an alteration common to most virally induced tumors. Rat fibroblasts transformed with wild-type or a temperature-sensitive Fujinami sarcoma virus (FSV) were studied in order to determine the mechanisms underlying the increased transport. Five- to tenfold increases in total cellular glucose transporter protein in response to transformation were accompanied by similar increases in transporter messenger RNA levels. This, in turn, was preceded by an absolute increase in the rate of glucose transporter gene transcription within 30 minutes after shift of the temperature-sensitive FSV-transformed cells to the permissive temperature. The transporter messenger RNA levels in transformed fibroblasts were higher than those found in proliferating cells maintained at the nonpermissive temperature. The activation of transporter gene transcription by transformation represents one of the earliest known effects of oncogenesis on the expression of a gene encoding a protein of well-defined function.

A pilot study of prophylactic donor lymphocyte infusions to prevent relapse in adult acute lymphoblastic leukemias after allogeneic hematopoietic stem cell transplantation.

The outcome of patients with acute lymphoblastic leukemia (ALL) receiving therapeutic donor lymphocyte infusions (DLIs) in relapse after stem cell transplantation (SCT) is poor. We analyzed the impact of prophylactic DLIs in ALL on chimerism and sustained complete remission (CR). Eighty-five patients with ALL were allografted between January 1998 and September 2004. Twenty-six of them received prophylactic DLIs and were included in this analysis. A total of 12 of 13 patients, who were treated with mixed chimerism (MC) converted to complete donor chimerism (92%) and 10 of 12 patients had persistent donor chimerism and sustained CR during subsequent follow-up. Overall, 18 of 26 patients developed graft-versus-host disease (GVHD) after DLIs (69%), acute GVHD in 46 and chronic GVHD in 62%. After a median follow-up of 42 months (14-72) after SCT, 18 of 26 patients (70%) are alive, 16 in CR. Probability of event-free survival (EFS) for patients treated with DLIs is 62%, and overall survival is 70% at 3 years. Our preliminary data support a graft-versus-leukemia effect of prophylactic DLIs able to induce stable donor chimerism and ongoing CR after SCT. As the accompanying GVHD rate was considerable, careful selection of patients for prophylactic DLIs is mandatory.

Structure and ligand specificity of the Drosophila melanogaster insulin receptor.

The insulin-binding and protein tyrosine kinase subunits of the Drosophila melanogaster insulin receptor homolog have been identified and characterized by using antipeptide antibodies elicited to the deduced amino acid sequence of the alpha and beta subunits of the human insulin receptor. In D. melanogaster embryos and cell lines, the insulin receptor contains insulin-binding alpha subunits of 110 or 120 kilodaltons (kDa), a 95-kDa beta subunit that is phosphorylated on tyrosine in response to insulin in intact cells and in vitro, and a 170-kDa protein that may be an incompletely processed receptor. All of the components are synthesized from a proreceptor, joined by disulfide bonds, and exposed on the cell surface. The beta subunit is recognized by an antipeptide antibody elicited to amino acids 1142 to 1162 of the human insulin proreceptor, and the alpha subunit is recognized by an antipeptide antibody elicited to amino acids 702 to 723 of the human proreceptor. Of the polypeptide ligands tested, only insulin reacts with the D. melanogaster receptor. Insulinlike growth factors type I and II, epidermal growth factor, and the silkworm insulinlike prothoracicotropic hormone are unable to stimulate autophosphorylation. Thus despite the evolutionary divergence of vertebrates and invertebrates, the essential features of the structure and intrinsic functions of the insulin receptor have been remarkably conserved.

Tissue localization of Drosophila melanogaster insulin receptor transcripts during development.

The Drosophila melanogaster insulin receptor (Drosophila insulin receptor homolog [dIRH]) is similar to its mammalian counterpart in deduced amino acid sequence, subunit structure, and ligand-stimulated protein tyrosine kinase activity. The function of this receptor in D. melanogaster is not yet known. However, a role in development is suggested by the observations that levels of insulin-stimulated kinase activity and expression of dIRH mRNA are maximal during Drosophila midembryogenesis. In this study, a 2.9-kilobase (kb) cDNA clone corresponding to both the dIRH tyrosine kinase domain and some of the 3' untranslated sequence was used to determine the tissue distribution of dIRH mRNA during development. Two principal mRNAs of 11 and 8.6 kb hybridized with the dIRH cDNA in Northern (RNA) blot analysis. The abundance of the 8.6-kb mRNA increased transiently in early embryos, whereas the 11-kb species was most abundant during midembryogenesis. A similar pattern of expression was previously determined by Northern analysis, using a dIRH genomic clone (L. Petruzzelli, R. Herrera, R. Arenas-Garcia, R. Fernandez, M. J. Birnbaum, and O. M. Rosen, Proc. Natl. Acad. Sci. USA 83:4710-4714, 1986). In situ hybridization revealed dIRH transcripts in the ovaries of adult flies, in which the transcripts appeared to be synthesized by nurse cells for eventual storage as maternal RNA in the mature oocyte. Throughout embryogenesis, dIRH transcripts were ubiquitously expressed, although after midembryogenesis, higher levels were detected in the developing nervous system. Nervous system expression remained elevated throughout the larval stages and persisted in the adult, in which the cortex of the brain and ganglion cells were among the most prominently labeled tissues. In larvae, the imaginal disk cells exhibited comparatively high levels of dIRH mRNA expression. The broad distribution of dIRH mRNA in embryos and imaginal disks is compatible with a role for dIRH in anabolic processes required for cell growth. The apparently elevated expression of dIRH mRNA in nervous tissue during mid- and late embryogenesis coincides with a period of active neurite outgrowth and suggests that dIRH may be involved in this process.

Reconstitution of an insulin signaling pathway in Xenopus laevis oocytes: coexpression of a mammalian insulin receptor and three different mammalian hexose transporters.

We report the functional expression of the mammalian muscle-adipocyte insulin-sensitive hexose transporter in Xenopus laevis oocytes. Oocytes microinjected with RNA synthesized in vitro showed enhanced hexose transport activity compared with uninjected controls. However, like the endogenous oocyte hexose transporter, activity was stimulated only twofold by 1 microM insulin. X. laevis oocytes injected with in vitro-synthesized RNA encoding the human insulin proreceptor expressed a functionally active insulin receptor that enhanced the insulin sensitivity of injected oocytes. This increase was not observed in oocytes expressing a mutant insulin receptor that lacked protein tyrosine kinase activity. In the presence of the coexpressed human insulin receptor, insulin induced a two- to threefold increase in hexose transport. The muscle-, brain-, and liver-type hexose carriers normally expressed in tissues with different responses to insulin exhibited the same insulin sensitivity when expressed in oocytes. This was observed whether or not the insulin signal was transduced through a coexpressed human insulin receptor or the endogenous oocyte insulin-like growth factor I receptor. We conclude that the expressed human insulin receptor is able to couple efficiently with preexisting postreceptor regulatory pathways in oocytes and that the regulation of hexose transport in these cells can be mediated through the combined actions of the expressed human insulin receptor and the endogenous oocyte insulin-like growth factor I receptor.

Insulin and insulinlike growth factor 1 (IGF-1) receptors during central nervous system development: expression of two immunologically distinct IGF-1 receptor beta subunits.

Insulin and insulinlike growth factor 1 (IGF-1) receptors are present in brain, yet their function remains obscure. Expression of these tyrosine kinase-bearing growth factor receptors during rat brain development was examined by using three antipeptide antibodies directed against epitopes in the beta subunits (AbP2, AbP4, and AbP5). All three antibodies recognized both insulin and IGF-1 receptors. Membranes were prepared from fetal brains (14 to 21 days of gestation), neonatal brain (postnatal day 1), and adult brain. Immunoblot analyses using AbP4 and AbP5 revealed a 92-kilodalton (kDa) protein that corresponded to the beta subunit of the insulin and IGF-1 receptors. Densitometric scanning of immunoblots indicated that receptor proteins were 4- to 10-fold more abundant in fetal brain membranes than in membranes from adult brain. Expression was highest during 16 to 18 days of gestation and declined thereafter to the relatively low level found in adult brain. Immunoblot analyses with AbP2 as well as ligand-activated receptor autophosphorylation revealed an additional protein of 97 kDa. This protein was phosphorylated in response to IGF-1 and was not directly recognized by AbP4 or AbP5. The covalent association of the 97-kDa protein with the 92-kDa beta subunit was indicated by the ability of AbP4 and AbP5 to immunoprecipitate both proteins under nonreducing conditions but only the 92-kDa protein after reduction. In contrast, AbP2 immunoprecipitated both proteins regardless of their association. This immunospecificity remained unchanged after deglycosylation of the isolated proteins. Two-dimensional tryptic phosphopeptide analysis showed that the 92- and 97-kDa subunits of the IGF-1 receptor are related but distinct proteins. Taken together, the data suggest that the 92- and 97-kDa subunits differ in primary amino acid sequence. Thus, two distinct beta subunits may be present in a single IGF-1 receptor in brain. These subunits have in common an epitope recognized by an antibody to the tyrosine kinase domain (AbP2) but differ in regions thought to be important in receptor kinase regulation and signal transduction.

Functional expression of mammalian glucose transporters in Xenopus laevis oocytes: evidence for cell-dependent insulin sensitivity.

We report the functional expression of two different mammalian facilitative glucose transporters in Xenopus oocytes. The RNAs encoding the rat brain and liver glucose transporters were transcribed in vitro and microinjected into Xenopus oocytes. Microinjected cells showed a marked increase in 2-deoxy-D-glucose uptake as compared with controls injected with water. 2-Deoxy-D-glucose uptake increased during the 5 days after microinjection of the RNAs, and the microinjected RNAs were stable for at least 3 days. The expression of functional glucose transporters was dependent on the amount of RNA injected. The oocyte-expressed transporters could be immunoprecipitated with anti-brain and anti-liver glucose transporter-specific antibodies. Uninjected oocytes expressed an endogenous transporter that appeared to be stereospecific and inhibitable by cytochalasin B. This transporter was kinetically and immunologically distinguishable from both rat brain and liver glucose transporters. The uniqueness of this transporter was confirmed by Northern (RNA) blot analysis. The endogenous oocyte transporter was responsive to insulin and to insulinlike growth factor I. Most interestingly, both the rat brain and liver glucose transporters, which were not insulin sensitive in the tissues from which they were cloned, responded to insulin in the oocyte similarly to the endogenous oocyte transporter. These data suggest that the insulin responsiveness of a given glucose transporter depends on the type of cell in which the protein is expressed. The expression of hexose transporters in the microinjected oocytes may help to identify tissue-specific molecules involved in hormonal alterations in hexose transport activity.

A possible role for a mammalian facilitative hexose transporter in the development of resistance to drugs.

We show that D- but not L-hexoses modulate the accumulation of radioactive vinblastine in injected Xenopus laevis oocytes expressing the murine Mdr1b P-glycoprotein. We also show that X. laevis oocytes injected with RNA encoding the rat erythroid/brain glucose transport protein (GLUT1) and expressing the corresponding functional transporter exhibit a lower accumulation of [3H]vinblastine and show a greater capacity to extrude the drug than do control oocytes not expressing the rat GLUT1 protein. Cytochalasin B and phloretin, two inhibitors of the mammalian facilitative glucose transporters, can overcome the reduced drug accumulation conferred by expression of the rat GLUT1 protein in Xenopus oocytes but have no significant effect on the accumulation of drug by Xenopus oocytes expressing the mouse Mdr1b P-glycoprotein. These drugs also increase the accumulation of [3H]vinblastine in multidrug-resistant Chinese hamster ovary cells. Cytochalasin E, an analog of cytochalasin B that does not affect the activity of the facilitative glucose transporter, has no effect on the accumulation of vinblastine by multidrug-resistant Chinese hamster cells or by oocytes expressing either the mouse Mdr1b P-glycoprotein or the GLUT1 protein. In all three cases, the drug verapamil produces a profound effect on the cellular accumulation of vinblastine. Interestingly, although immunological analysis indicated the presence of massive amounts of P-glycoprotein in the multidrug-resistant cells, immunological and functional studies revealed only a minor increase in the expression of a hexose transporter-like protein in resistant versus drug-sensitive cells. Taken together, these results suggest the participation of the mammalian facilitative glucose transporter in the development of drug resistance.

Trithorax and ASH1 interact directly and associate with the trithorax group-responsive bxd region of the Ultrabithorax promoter.

Trithorax (TRX) and ASH1 belong to the trithorax group (trxG) of transcriptional activator proteins, which maintains homeotic gene expression during Drosophila development. TRX and ASH1 are localized on chromosomes and share several homologous domains with other chromatin-associated proteins, including a highly conserved SET domain and PHD fingers. Based on genetic interactions between trx and ash1 and our previous observation that association of the TRX protein with polytene chromosomes is ash1 dependent, we investigated the possibility of a physical linkage between the two proteins. We found that the endogenous TRX and ASH1 proteins coimmunoprecipitate from embryonic extracts and colocalize on salivary gland polytene chromosomes. Furthermore, we demonstrated that TRX and ASH1 bind in vivo to a relatively small (4 kb) bxd subregion of the homeotic gene Ultrabithorax (Ubx), which contains several trx response elements. Analysis of the effects of ash1 mutations on the activity of this regulatory region indicates that it also contains ash1 response element(s). This suggests that ASH1 and TRX act on Ubx in relatively close proximity to each other. Finally, TRX and ASH1 appear to interact directly through their conserved SET domains, based on binding assays in vitro and in yeast and on coimmunoprecipitation assays with embryo extracts. Collectively, these results suggest that TRX and ASH1 are components that interact either within trxG protein complexes or between complexes that act in close proximity on regulatory DNA to maintain Ubx transcription.

Simulation as a tool for improving acquisition of neonatal resuscitation skills for obstetric residents.

OBJECTIVE: Our goal was to compare the confidence, knowledge, and performance of obstetric residents taught initial neonatal resuscitation steps in a simulation-based versus lecture-based format. METHODS: Our study was a prospective randomized controlled trial of 33 obstetric residents. Baseline confidence, knowledge, and clinical skills assessments were performed. Subjects were randomized to traditional lecture (n = 14) or simulation-based (n = 19) neonatal resuscitation curriculum with a focus on initial steps. Follow-up assessments were performed at 3 and 6 months. Total confidence, knowledge, and clinical performance scores and change from baseline in these scores were calculated and compared between groups. RESULTS: Both the lecture-based and simulated-based groups demonstrated significant improvement in confidence, knowledge, and performance over time. However, compared with the lecture group, the magnitude of the mean change from baseline in performance scores was significantly greater in the simulation group at 3 months (2.9 versus 10.1; p < 0.001), but not at 6 months (7.0 versus 9.3; p = 0.11). CONCLUSIONS: Our study demonstrates the superiority of simulation in teaching obstetric residents initial neonatal resuscitation steps compared with a traditional lecture format. Skills are retained for upwards of 3-6 months. Refresher instruction by 6 months post-instruction may be beneficial.

Self-association of the SET domains of human ALL-1 and of Drosophila TRITHORAX and ASH1 proteins.

The human ALL-1 gene is involved in acute leukemia through gene fusions, partial tandem duplications or a specific deletion. Several sequence motifs within the ALL-1 protein, such as the SET domain, PHD fingers and the region with homology to DNA methyl transferase are shared with other proteins involved in transcription regulation through chromatin alterations. However, the function of these motifs is still not clear. Studying ALL-1 presents an additional challenge because the gene is the human homologue of Drosophila trithorax. The latter is a member of the trithorax-Polycomb gene family which acts to determine the body pattern of Drosophila by maintaining expression or repression of the Antennapedia-bithorax homeotic gene complex. Here we apply yeast two hybrid methodology, in vivo immunoprecipitation and in vitro 'pull down' techniques to show self association of the SET motifs of ALL-1, TRITHORAX and ASH1 proteins (Drosophila ASH1 is encoded by a trithorax-group gene). Point mutations in evolutionary conserved residues of TRITHORAX SET, abolish the interaction. SET-SET interactions might act in integrating the activity of ALL-1 (TRX and ASH1) protein molecules, simultaneously positioned at different maintenance elements and directing expression of the same or different target genes.