The National Sleep Research Resource: making data findable, accessible, interoperable, reusable and promoting sleep science.

This paper presents a comprehensive overview of the National Sleep Research Resource (NSRR), a National Heart Lung and Blood Institute-supported repository developed to share data from clinical studies focused on the evaluation of sleep disorders. The NSRR addresses challenges presented by the heterogeneity of sleep-related data, leveraging innovative strategies to optimize the quality and accessibility of available datasets. It provides authorized users with secure centralized access to a large quantity of sleep-related data including polysomnography, actigraphy, demographics, patient-reported outcomes, and other data. In developing the NSRR, we have implemented data processing protocols that ensure de-identification and compliance with FAIR (Findable, Accessible, Interoperable, Reusable) principles. Heterogeneity stemming from intrinsic variation in the collection, annotation, definition, and interpretation of data has proven to be one of the primary obstacles to efficient sharing of datasets. Approaches employed by the NSRR to address this heterogeneity include (1) development of standardized sleep terminologies utilizing a compositional coding scheme, (2) specification of comprehensive metadata, (3) harmonization of commonly used variables, and (3) computational tools developed to standardize signal processing. We have also leveraged external resources to engineer a domain-specific approach to data harmonization. We describe the scope of data within the NSRR, its role in promoting sleep and circadian research through data sharing, and harmonization of large datasets and analytical tools. Finally, we identify opportunities for approaches for the field of sleep medicine to further support data standardization and sharing.

Taxonomic revision of the native bee subgenus Parasphecodes Smith 1853 in Australia (Hymenoptera: Halictidae: Halictini: Lasioglossum Curtis 1833).

The Australian Lasioglossum Curtis 1833 subgenus Parasphecodes Smith 1853 is revised. Currently, Parasphecodes has 92 named, described species. The monotypic Lasioglossum subgenus Pseudochilalictus Michener 1965 is synonymised with Parasphecodes and its species, L. imitator Michener 1965, is recombined into Parasphecodes. The single known species from New Guinea, L. (Parasphecodes) permetallicum Michener 1965, is included in this revision. Eighteen new species are erected, 69 names are placed into synonymy, 20 new sex associations made and three species currently placed in Parasphecodes are recombined into the Lasioglossum subgenus Ctenonomia Cameron 1903. This revision resolved there are 40 valid species for Parasphecodes. Valid species for Lasioglossum (Parasphecodes) without synonymies are as follows: L. imitator, L. lichatus (Smith 1853), L. loweri (Cockerell 1905), L. olgae (Rayment 1935), L. permetallicum, L. turneri (Cockerell 1914d) and L. waterhousei (Cockerell 1915a). New synonymies proposed for Lasioglossum (Parasphecodes) are as follows: Lasioglossum (Pseudochilalictus Michener 1965) new synonymy = Lasioglossum (Parasphecodes); L. cirriferum (Cockerell 1910) new synonymy, L. insigne (Meyer 1920) new synonymy and L. grande (Meyer 1920) new synonymy = L. altichus (Smith 1853); L. paramelaenum (Cockerell 1922) new synonymy = L. atronitens (Cockerell 1914a); L. bribiense (Cockerell 1916) new synonymy, L. bribiensiforme (Cockerell 1930a) new synonymy, L. butleri (Rayment 1935) new synonymy, L. frenchi (Rayment 1935) new synonymy, L. frenchellum Michener 1965 new synonymy, L. sordidulum (Cockerell 1914c) new synonymy and L. patongensis (Rayment 1948) new synonymy = L. bryotrichum (Cockerell 1912a); L. fumidicaudum (Cockerell 1914b) new synonymy and L. noachinum (Cockerell 1914b) new synonymy = L. carbonarium (Smith 1853); L. cervicale (Cockerell 1915b) new synonymy and L. zamelanum (Cockerell 1930a) new synonymy = L. dissimulator (Cockerell 1914b); L. wilmatae (Cockerell 1929c) new synonymy = L. excultum (Cockerell 1913b); L. arciferum (Cockerell 1914b) new synonymy, L. atrorufescens (Cockerell 1914b) new synonymy, L. fulviventre (Friese 1924) new synonymy, L. leptospermi (Cockerell 1916) new synonymy, L. lichatinum (Cockerell 1922) new synonymy, L. leucorhinum (Cockerell 1926) new synonymy, L. proximum (Rayment 1947) new synonymy, L. testaciventre (Rayment 1953) new synonymy, L. tilachus (Smith 1853) new synonymy, L. tilachiforme (Cockerell 1907) new synonymy, L. tuchilas (Smith 1853) new synonymy, L. anhybodinum (Cockerell 1930a) new synonymy, L. hybodinum (Cockerell 1912a) new synonymy, L. tripunctatum (Cockerell 1929c) new synonymy and L. warburtoni (Cockerell 1906) new synonymy = L. hilactus (Smith 1853); L. frenchi (Cockerell 1904) new synonymy, L. schomburgki (Cockerell 1910) new synonymy, L. speculiferum (Cockerell 1912a) new synonymy, L. sextum (Cockerell 1910) new synonymy, L. solis (Cockerell 1922) new synonymy, L. vermiculatum (Cockerell 1914b) new synonymy and L. vulneratum (Cockerell 1910) new synonymy = L. hiltacus (Smith 1853); L. hirtiventre (Cockerell 1922) new synonymy, L. niveorufum (Friese 1924) new synonymy, L. submeracum (Cockerell 1930a) new synonymy and L. froggatti (Cockerell 1905) new synonymy = L. lacthius (Smith 1853); L. basilautum (Cockerell 1910) new synonymy, L. doddi (Cockerell 1914c) new synonymy, L. paracolletinum (Cockerell 1910) new synonymy, L. pilicolle (Friese 1924) new synonymy, L. scutellatum (Friese 1924) new synonymy and L. vau (Cockerell 1910) new synonymy = L. leichardti (Cockerell 1906); L. annexum (Cockerell 1922) new synonymy, L. latissimum (Cockerell 1915b) new synonymy, L. microdontum (Cockerell 1912a) new synonymy, L. recessum (Cockerell 1914d) new synonymy, L. longmani (Cockerell 1922) new synonymy, L. recantans (Cockerell 1912a) new synonymy and L. rufotegulare (Cockerell 1914e) new synonymy = L. melbournense (Cockerell 1904); L. trimaculatum (Friese 1924) new synonymy = L. musicum (Cockerell 1913a); L. gentianae (Rayment 1951) new synonymy = L. subrussatum (Cockerell 1922); L. fultoni (Cockerell 1914b) new synonymy, L. gibbosum (Friese 1924) new synonymy, L. niveatum (Meyer 1920) new synonymy, L. punctatissimus (Meyer 1920) new synonymy, L. rhodopterum (Cockerell 1914e) new synonymy, L. rubriventre (Friese 1924) new synonymy, L. subfultoni (Cockerell 1930a) new synonymy, L. tepperi (Cockerell 1905) new synonymy, L. notescens (Cockerell 1930a) new synonymy and L. rufulum (Friese 1924) new synonymy = L. sulthica (Smith 1853); L. submoratum (Cockerell 1930a) new synonymy and L. perustum (Cockerell 1914d) new synonymy = L. taluchis (Smith 1853). Eighteen new species are described as follows: L. acristum Walker & Sparks, L. altum Walker & Sparks, L. aspereticulum Walker & Sparks, L. atropum Walker & Sparks, L. bimelasmum Walker & Sparks, L. bipenicillum Walker & Sparks, L. bitrichum Walker & Sparks, L. blyscanatum Walker & Sparks, L. brevipectinatum Walker & Sparks, L. capronum Walker & Sparks, L. ferruginum Walker & Sparks, L. flexosum Walker & Sparks, L. laevidiscum Walker & Sparks, L. recavum Walker & Sparks, L. reticulum Walker & Sparks, L. rutrum Walker & Sparks, L. variegatum Walker & Sparks and L. wcisloi Walker & Sparks. New subgeneric classifications are as follows: L. (Pseudochilalictus) imitator = L. (Parasphecodes) imitator new status, Halictus clarigaster Cockerell 1918 = L. (Ctenonomia) clarigaster new status, Halictus forresti Cockerell 1906 = L. (Ctenonomia) forresti new status, and Halictus tribuarius Rayment 1935 = L. (Ctenonomia) tribuarium new status. These species names, all described by Smith 1853, are anagrams of Halictus. Therefore, they are nouns in apposition and should retain their original species designations as: Lasioglossum (Parasphecodes) altichus (Smith 1853), Lasioglossum (Parasphecodes) hilactus (Smith 1853), Lasioglossum (Parasphecodes) hiltacus (Smith 1853), Lasioglossum (Parasphecodes) lacthius (Smith 1853), Lasioglossum (Parasphecodes) lichatus (Smith 1853), Lasioglossum (Parasphecodes) sulthica (Smith 1853), Lasioglossum (Parasphecodes) talchius (Smith 1853), Lasioglossum (Parasphecodes) taluchis (Smith 1853), Lasioglossum (Parasphecodes) tilachus (Smith 1853) and Lasioglossum (Parasphecodes) tuchilas (Smith 1853). All 40 valid Parasphecodes species, as well as the three species recombined to Ctenonomia, are redescribed. For the Parasphecodes species, keys to both sexes, character groups, taxonomy, citations, species diagnoses, comments, descriptions, scanning electron micrographs, colour montage images, distribution maps, male genitalia and S7S8 line drawings are provided to assist with species identifications.

Variant-dependent heterogeneity in amyloid ß burden in autosomal dominant Alzheimer's disease: cross-sectional and longitudinal analyses of an observational study.

BACKGROUND: Insights gained from studying individuals with autosomal dominant Alzheimer's disease have broadly influenced mechanistic hypotheses, biomarker development, and clinical trials in both sporadic and dominantly inherited Alzheimer's disease. Although pathogenic variants causing autosomal dominant Alzheimer's disease are highly penetrant, there is substantial heterogeneity in levels of amyloid ß (Aß) between individuals. We aimed to examine whether this heterogeneity is related to disease progression and to investigate the association with mutation location within PSEN1, PSEN2, or APP. METHODS: We did cross-sectional and longitudinal analyses of data from the Dominantly Inherited Alzheimer's Network (DIAN) observational study, which enrols individuals from families affected by autosomal dominant Alzheimer's disease. 340 participants in the DIAN study who were aged 18 years or older, had a history of autosomal dominant Alzheimer's disease in their family, and who were enrolled between September, 2008, and June, 2019, were included in our analysis. 206 participants were carriers of pathogenic mutations in PSEN1, PSEN2, or APP, and 134 were non-carriers. 62 unique pathogenic variants were identified in the cohort and were grouped in two ways. First, we sorted variants in PSEN1, PSEN2, or APP by the affected protein domain. Second, we divided PSEN1 variants according to position before or after codon 200. We examined variant-dependent variability in Aß biomarkers, specifically Pittsburgh-Compound-B PET (PiB-PET) signal, levels of CSF Aß1-42 (Aß42), and levels of Aß1-40 (Aß40). FINDINGS: Cortical and striatal PiB-PET signal showed striking variant-dependent variability using both grouping approaches (p<0·0001), despite similar progression on the clinical dementia rating (p>0·7), and CSF Aß42 levels (codon-based grouping: p=0·49; domain-based grouping: p=0·095). Longitudinal PiB-PET signal also varied across codon-based groups, mirroring cross-sectional analyses. INTERPRETATION: Autosomal dominant Alzheimer's disease pathogenic variants showed highly differential temporal and regional patterns of PiB-PET signal, despite similar functional progression. These findings suggest that although increased PiB-PET signal is generally seen in autosomal dominant Alzheimer's disease, higher levels of PiB-PET signal at an individual level might not reflect more severe or more advanced disease. Our results have high relevance for ongoing clinical trials in autosomal dominant Alzheimer's disease, including those using Aß PET as a surrogate marker of disease progression. Additionally, and pertinent to both sporadic and autosomal dominant Alzheimer's disease, our results suggest that CSF and PET measures of Aß levels are not interchangeable and might reflect different Aß-driven pathobiological processes. FUNDING: National Institute on Aging, Doris Duke Charitable Foundation, German Center for Neurodegenerative Diseases, Japanese Agency for Medical Research and Development.

Bardet-Biedl Syndrome ciliopathy is linked to altered hematopoiesis and dysregulated self-tolerance.

Bardet-Biedl Syndrome (BBS) is a pleiotropic genetic disease caused by the dysfunction of primary cilia. The immune system of patients with ciliopathies has not been investigated. However, there are multiple indications that the impairment of the processes typically associated with cilia may have influence on the hematopoietic compartment and immunity. In this study, we analyze clinical data of BBS patients and corresponding mouse models carrying mutations in Bbs4 or Bbs18. We find that BBS patients have a higher prevalence of certain autoimmune diseases. Both BBS patients and animal models have altered red blood cell and platelet compartments, as well as elevated white blood cell levels. Some of the hematopoietic system alterations are associated with BBS-induced obesity. Moreover, we observe that the development and homeostasis of B cells in mice is regulated by the transport complex BBSome, whose dysfunction is a common cause of BBS. The BBSome limits canonical WNT signaling and increases CXCL12 levels in bone marrow stromal cells. Taken together, our study reveals a connection between a ciliopathy and dysregulated immune and hematopoietic systems.

Examining Cognitive Decline Across Black and White Participants in the Harvard Aging Brain Study.

BACKGROUND: Black Americans are approximately twice as likely to develop dementia as compared to White Americans and the magnitude of this disparity is often attributed to a variety of factors that include psychosocial and vascular risk factors. However, less is known about the potential contribution of Alzheimer's disease pathological differences. OBJECTIVE: To examine potential differences incross-sectional and longitudinal cognitive performance in black and white participants who were clinically normal at baseline. METHODS: 296 participants (48 African-American/black participants) underwent MRI and amyloid PET at baseline. Linear mixed models were used to examine the main effects of race, years of education, reading ability, Framingham Heart Study cardiovascular risk score (FHS-CVD), white matter hyperintensities (WMH), and amyloid (Aß) burden on the Preclinical Alzheimer Cognitive Composite-5 (PACC5). RESULTS: Lower levels of educationalattainment and reading ability were found for blacks compared to whites. By contrast, no differences in FHS-CVD, WMH, or Aß were found by racial group. Baseline differences in PACC5 score were attenuated after adjusting for educationalfactors, vascular factors, and Aß, but remained lower for blacks compared to whites (ß= -0.24, p = 0.014). Further, blacks demonstrated a faster rate of PACC5 decline longitudinally compared to whites (ß â€Š= -0.055, p = 0.025) after adjusting for covariates. CONCLUSION: Accounting for educationalfactors, vascular factors, and Aß burden diminished, but did not eliminate, racial differences in PACC5 performance longitudinally. Understanding potential differences in longitudinal cognitive outcomes by race may be important for upcoming secondary prevention trials.

The Endocrine and Metabolic Characteristics of a Large Bardet-Biedl Syndrome Clinic Population.

Context: Bardet-Biedl syndrome (BBS) is a rare autosomal recessive disorder in which previous reports have described obesity and a metabolic syndrome. Objective: We describe the endocrine and metabolic characteristics of a large BBS population compared with matched control subjects. Design: We performed a case-control study. Setting: This study was performed at a hospital clinic. Patients: Study patients had a clinical or genetic diagnosis of BBS. Main Outcome Measurements: Our study determined the prevalence of a metabolic syndrome in our cohort. Results: A total of 152 subjects were studied. Eighty-four (55.3%) were male. Mean (± standard deviation) age was 33.2 ± 1.0 years. Compared with age-, sex-, and body mass index-matched control subjects, fasting glucose and insulin levels were significantly higher in subjects with BBS (glucose: BBS, 5.2 ± 1.2 mmol/L vs control, 4.9 ± 0.9 mmol/L, P = 0.04; insulin: BBS, 24.2 ± 17.0 pmol/L vs control, 14.2 ± 14.8 pmol/L, P < 0.001). Serum triglycerides were significantly higher in subjects with BBS (2.0 ± 1.2 mmol/L) compared with control subjects (1.3 ± 0.8 mmol/L; P < 0.001), but total cholesterol, high-density lipoprotein, and low-density lipoprotein were similar in both groups. Systolic blood pressure was higher in the BBS group (BBS, 135 ± 18 mm Hg vs control subjects, 129 ± 16 mm Hg; P = 0.02). Alanine transaminase was raised in 34 (26.8%) subjects with BBS, compared with five (8.9%) control subjects (P = 0.01). The rate of metabolic syndrome, determined using International Diabetes Federation criteria, was significantly higher in the BBS group (54.3%) compared with control subjects (26% P < 0.001). Twenty-six (19.5%) of male subjects with BBS were hypogonadal (serum testosterone, 9.9 ± 5.3 mmol/L), but significant pituitary abnormalities were uncommon. Subclinical hypothyroidism was present in 24 of 125 (19.4%) patients with BBS, compared with 3 of 65 (4.6%) control subjects (P = 0.01). Conclusions: Insulin resistance and the metabolic syndrome are increased in adult patients with BBS compared with matched control subjects. Increased subclinical hypothyroidism in the BBS cohort needs further investigation.

Risk Factors for Severe Renal Disease in Bardet-Biedl Syndrome.

Bardet-Biedl syndrome is a rare autosomal recessive, multisystem disease characterized by retinal dystrophy, renal malformation, obesity, intellectual disability, polydactyly, and hypogonadism. Nineteen disease-causing genes (BBS1-19) have been identified, of which mutations in BBS1 are most common in North America and Europe. A hallmark of the disease, renal malformation is heterogeneous and is a cause of morbidity and mortality through the development of CKD. We studied the prevalence and severity of CKD in 350 patients with Bardet-Biedl syndrome-related renal disease attending the United Kingdom national Bardet-Biedl syndrome clinics to further elucidate the phenotype and identify risk indicators of CKD. Overall, 31% of children and 42% of adults had CKD; 6% of children and 8% of adults had stage 4-5 CKD. In children, renal disease was often detected within the first year of life. Analysis of the most commonly mutated disease-associated genes revealed that, compared with two truncating mutations, two missense mutations associated with less severe CKD in adults. Moreover, compared with mutations in BBS10, mutations in BBS1 associated with less severe CKD or lack of CKD in adults. Finally, 51% of patients with available ultrasounds had structural renal abnormalities, and 35% of adults were hypertensive. The presence of structural abnormalities or antihypertensive medication also correlated statistically with stage 3b-5 CKD. This study describes the largest reported cohort of patients with renal disease in Bardet-Biedl syndrome and identifies risk factors to be considered in genetic counseling.

Health Literacy and Preferences for Sources of Child Health Information of Mothers With Infants in the Neonatal Intensive Care Unit.

BACKGROUND: Parents of infants hospitalized in the neonatal intensive care unit (NICU) frequently need guidance to prepare them for the care and health promotion of their child after hospital discharge. The health literacy of the parents should be considered so that education can be tailored to meet their needs. It is also important to understand the parents' preferences for how, and from whom, they receive education. PURPOSE: The purpose of this study was to identify health literacy levels of parents of infants in an NICU and preferences for who they want to provide them with education. METHODS: An exploratory, descriptive design was used to assess participant health literacy and preferences for obtaining child health information. Only mothers (no fathers) with babies in the NICU were available to complete the survey. Mean participant age was 26.4 years (SD = 6.7). RESULTS: Participants had a mean Rapid Estimate of Adult Literacy in Medicine, Revised, score of 5.64 (SD = 2.4), indicating a low level of health literacy. Questions regarding when to administer medication were correctly answered by 69% of participants. Proper medication dosage was understood by 92% of participants; however, only 30% were able to correctly convert measurements. One-on-one discussions with a physician were the preferred source of health information for 80% of participants. IMPLICATIONS FOR PRACTICE/RESEARCH: The current exploratory study provides new information that will help inform the development of future studies and increase awareness of nurses regarding health literacy and the specific types of skills for which parents need the most help.

Research Champions: An Initiative to Improve Use of Research Evidence in Nursing Practice.

The implementation of the Research Champions program was an effective strategy to increase the confidence of direct care nurses in research skills, a goal for staff development educators. Postprogram questionnaires conducted at 12 months assessed participants' confidence in specific areas: critique of research manuscripts, comprehension of research statistics, knowledge of the ethics of research, and using research in practice. Data supported that participants' confidence increased in all areas assessed.

Feasibility of Two Educational Methods for Teaching New Mothers: A Pilot Study.

BACKGROUND: Printed health educational materials are commonly issued to prepare patients for hospital discharge. Teaching methods that engage multiple senses have been shown to positively affect learning outcomes, suggesting that paper materials may not be the most effective approach when educating new mothers. In addition, many written patient educational materials do not meet national health literacy guidelines. Videos that stimulate visual and auditory senses provide an alternative, potentially more effective, strategy for delivering health information. The acceptability of these methods, as perceived by nurses executing patient education initiatives, is important for determining the most appropriate strategy. OBJECTIVE: The purpose of this study was to determine the feasibility of 2 educational methods for teaching new mothers how to care for themselves and their infants after hospital discharge. Feasibility was measured by adequate enrollment, acceptability of the intervention to patients and nurses, and initial efficacy. METHODS: New mothers (n=98) on a Mother-Baby Unit received health information focused on self-care and infant care delivered as either simple printed materials or YouTube videos on an iPad. Mothers completed a pretest, post-test, and an acceptability survey. Following completion of the initiative, nurses who participated in delivering the health education using one of these 2 methods were asked to complete a survey to determine their satisfaction with and confidence in using the materials. RESULTS: Mothers, on average, were 26 years old; 72% had a high school education; and 41% were African American. The improvement in knowledge scores was significantly higher for the iPad group (8.6% vs 4.4%, P=.02) compared to the pamphlet group. Group (B=4.81, P=.36) and time (B=6.12, P<.001) significantly affected scores, while no significant interaction effect was observed (B=5.69, P=.09). There were no significant differences in responses between the groups (all P values >.05). The nurses had a mean age of 44.3 years (SD 13.9) and had, on average, 16.6 years of experience (SD 13.8). The nurses felt confident and satisfied administering both educational modalities. CONCLUSIONS: The pamphlet and iPad were identified as feasible and acceptable modalities for educating new mothers about self-care and infant care, though the iPad was more effective in improving knowledge. Understanding the acceptability of different teaching methods to patient educators is important for successful delivery of informational materials at discharge.

Systematics of the Monomorium rothsteini Forel species complex (Hymenoptera: Formicidae), a problematic ant group in Australia.

A recent molecular, morphological and distributional analysis of Monomorium rothsteini demonstrated that it comprises many separately evolving lineages that could be recognised morphologically and/or genetically based on mitochondrial DNA sequences. Based on these results M. rothsteini is revised, resulting in four species being brought out of synonymy (M. bogischi Wheeler, M. leda Forel, M. humilior Forel and M. subapterum Wheeler) and 18 new species recognised: M. broschorum n. sp., M. capeyork n. sp., M. eremoides n. sp., M. eremum n. sp., M. geminum n. sp., M. hertogi n. sp., M. hoffmanni n. sp., M. kidman n. sp., M. maryannae n. sp., M. merepah n. sp., M. mitchell n. sp., M. oodnadatta n. sp., M. pilbara n. sp., M. speculum n. sp., M. stagnum n. sp., M. tenebrosum n. sp., M. topend n. sp., M. torrens n. sp. Monomorium rothsteini v. doddi Santschi is recognised as a valid synonomy of M. rothsteini s.str. Along with M. rothsteini Forel s. str., there are now 23 described species in the complex, however it likely comprises many more species given the number of additional CO1 lineages and morphotypes that remain unresolved due to incomplete data. Biological notes are provided as well as a key to workers, descriptions, images and distribution maps for each species. 

Roles of maternal effects and nuclear genetic composition change across the life cycle of crop-wild hybrids.

• Premise of the study: The fitness of an offspring may depend on its nuclear genetic composition (via both parental genotypes) as well as on genetic maternal effects (via only the maternal parent). Understanding the relative importance of these two genetic factors is particularly important for research on crop-wild hybridization, since traits with important genetic maternal effects (e.g., seed size) often differ among crops and their relatives. We hypothesized that the effects of these genetic factors on fitness components would change across the life cycle of hybrids.• Methods: We followed seed, plant size, and reproductive traits in field experiments with wild and four crop-wild hybrids of sunflower (Helianthus annuus), which differed in nuclear genetic composition and maternal parent (wild or F1 hybrid).• Key results: We identified strong genetic maternal effects for early life cycle characteristics, with seeds produced on an F1 mother having premature germination, negligible seed dormancy, and greater seedling size. Increased percentages of crop alleles also increased premature germination and reduced dormancy in seeds produced on a wild mother. For mature plants, nuclear genetic composition dominated: greater percentages of crop alleles reduced height, branching, and fecundity.• Conclusions: Particular backcrosses between hybrids and wilds may differentially facilitate movement of crop alleles into wild populations due to their specific features. For example, backcross seeds produced on wild mothers can persist in the seed bank, illustrating the importance of genetic maternal effects, whereas backcross individuals with either wild or F1 mothers have high fecundity, resulting from their wild-like nuclear genetic composition.

Topoisomerase II binds importin alpha isoforms and exportin/CRM1 but does not shuttle between the nucleus and cytoplasm in proliferating cells.

Resistance to anticancer drugs that target DNA topoisomerase II (topo II) isoforms alpha and/or beta is associated with decreased nuclear and increased cytoplasmic topo IIalpha. Earlier studies have confirmed that functional nuclear localization and export signal sequences (NLS and NES) are present in both isoforms. In this study, we show that topo II alpha and beta bind and are imported into the nucleus by importin alpha1, alpha3, and alpha5 in conjunction with importin beta. Topo IIalpha also binds exportin/CRM1 in vitro. However, wild-type topo IIalpha has only been observed in the cytoplasm of cells that are entering plateau phase growth. This suggests that topo IIalpha may shuttle between the nucleus and the cytoplasm with the equilibrium towards the nucleus in proliferating cells but towards the cytoplasm in plateau phase cells. The CRM1 inhibitor Leptomycin B increases the nuclear localization of GFP-tagged topo IIalpha with a mutant NLS, suggesting that its export is being inhibited. However, homokaryon shuttling experiments indicate that fluorescence-tagged wild-type topo II alpha and beta proteins do not shuttle in proliferating Cos-1 or HeLa cells. We conclude that topo II alpha and beta nuclear export is inhibited in proliferating cells so that these proteins do not shuttle.

Mutational analysis of ionizable residues proximal to the cytoplasmic interface of membrane spanning domain 3 of the multidrug resistance protein, MRP1 (ABCC1): glutamate 1204 is important for both the expression and catalytic activity of the transporter.

The multidrug resistance protein MRP1 is an ATP-dependent transporter of organic anions and chemotherapeutic agents. A significant number of ionizable amino acids are found in or proximal to the 17 transmembrane (TM) helices of MRP1, and we have investigated 6 of these at the cytoplasmic interface of TM13-17 for their role in MRP1 expression and transport activity. Opposite charge substitutions of TM13 Arg(1046) and TM15 Arg(1131) did not alter MRP1 expression nor did they substantially affect activity. In contrast, opposite charge substitutions of TM16 Arg(1202) and Glu(1204) reduced protein expression by >80%; however, MRP1 expression was not affected when Arg(1202) and Glu(1204) were replaced with neutral or same-charge residues. In addition, organic anion transport levels of the R1202L, R1202G, and R1202K mutants were comparable with wild-type MRP1. In contrast, organic anion transport by E1204L was substantially reduced, whereas transport by E1204D was comparable with wild-type MRP1, with the notable exception of GSH. Opposite charge substitutions of TM16 Arg(1197) and TM17 Arg(1249) did not affect MRP1 expression but substantially reduced transport. Mutants containing like-charge substitutions of Arg(1197) or Arg(1249) were also transport-inactive and no longer bound leukotriene C(4). In contrast, substrate binding by the transport-compromised E1204L mutant remained intact. Furthermore, vanadate-induced trapping of azido-ADP by E1204L was dramatically increased, indicating that this mutation may cause a partial uncoupling of the catalytic and transport activities of MRP1. Thus, Glu(1204) serves a dual role in membrane expression of MRP1 and a step in its catalytic cycle subsequent to initial substrate binding.