'Building bridges': reflections and recommendations for co-producing health research

BACKGROUND

Co-produced research is when all stakeholders, including experts by experience and researchers, work together to conceptualise, design, deliver and disseminate research to enhance understanding and knowledge. This type of participatory inquiry is being increasingly used across health research; however, it continues to be a complex area to navigate given existing institutional structures.

MAIN BODY

We collaborated across three independent co-produced research studies to share insights, reflections, and knowledge of our work in the fields of HIV, mental health, and disability research. We co-designed and delivered a three-hour online workshop at a conference to share these reflections using the metaphor of 'building bridges' to describe our co-production journey. We generated key principles of co-production from our different experiences working in each individual research project as well as together across the three projects. Our principles are to: (1) be kind, have fun and learn from each other; (2) share power (as much as you can with people); (3) connect with people you know and don't know; (4) remain connected; and (5) use clear and simple language.

CONCLUSION

We recommend that co-produced research needs additional funding, resource, and flexibility to remain impactful and ethical. Co-produced research teams need to be mindful of traditional power structures and ensure that the process is transparent, fair, and ethical. Addressing equality, diversity, and inclusion of traditionally underrepresented groups in research is essential as are the skills, expertise, and experiences of all members of the co-production team.

"I'm the Family Ringmaster and Juggler": Autistic Parents' Experiences of Parenting During the COVID-19 Pandemic

Background

Little is known about autistic parenthood. The literature that exists suggests that autistic parents can find it difficult to manage the everyday demands of parenting and domestic life. While emerging research has also highlighted more positive parenting experiences, greater understanding of autistic parenthood is needed.

Objective

This study sought to understand autistic parents' parenting experiences during the initial phase of the COVID-19 pandemic.

Methods

Thirty-five Australian autistic parents (95% women) of autistic children (aged 4-25 years) took part in semi-structured interviews designed to elicit their experiences of life during lockdown. We used reflexive thematic analysis using an inductive (bottom-up) approach to identify patterned meanings within the data set.

Results

Autistic parents repeatedly spoke of how the lockdown brought some initial relief from the intensity of their usual lives caring for their children. Nevertheless, most autistic parents felt that the "cumulative stress" of trying to juggle everything during lockdown proved very challenging, which eventually took its toll on parents' mental health. Parents were aware that they needed support but found it difficult to reach out to their usual social supports (including autistic friends) for help, and formal supports were virtually nonexistent. Consequently, they felt "very much forgotten." Nevertheless, they described how their connections with their children grew stronger over lockdown as they focused on nurturing their children's "mental health ahead of everything else."

Conclusions

Our analysis shows how challenging conventional life can be for autistic parents. Parenting requires grappling with a distinctive set of demands, which are usually partially manageable through the informal supports many autistic parents draw upon. The relative absence of informal supports during the pandemic, however, left them reliant on more formal supports, which were not forthcoming. Research is urgently needed to identify the most effective formal supports for autistic parents, ideally in partnership with autistic parents themselves.

Supporting Remote Survey Data Analysis by Co-researchers with Learning Disabilities through Inclusive and Creative Practices and Data Science Approaches

Through a process of robust co-design, we created a bespoke accessible survey platform to explore the role of co-researchers with learning disabilities (LDs) in research design and analysis. A team of co-researchers used this system to create an online survey to challenge public understanding of LDs [3]. Here, we describe and evaluate the process of remotely co-analyzing the survey data across 30 meetings in a research team consisting of academics and non-academics with diverse abilities amid new COVID-19 lockdown challenges. Based on survey data with >1,500 responses, we first co-analyzed demographics using graphs and art & design approaches. Next, co-researchers co-analyzed the output of machine learning-based structural topic modelling (STM) applied to open-ended text responses. We derived an efficient five-steps STM co-analysis process for creative, inclusive, and critical engagement of data by co-researchers. Co-researchers observed that by trying to understand and impact public opinion, their own perspectives also changed.

Toward Empathetic Autism Research: Developing an Autism-Specific Research Passport

Autistic adults sometimes report negative experiences of research participation. People have developed passports or toolkits in other areas where community members report dissatisfaction (e.g., health care, criminal justice). We created a Research Passport that autism researchers and autistic adults could use to support the inclusion of autistic adults as research participants. We designed and developed the Research Passport via an iterative design process. First, we gathered ideas for a Research Passport via focus groups with autistic adults without an intellectual disability (ID) (n = 9) and autism researchers (n = 6; one of whom was autistic). We found that the Research Passport (1) was a useful idea, but not a panacea for all issues in autism research, (2) needed to be universal and flexible, and (3) could have a broad remit (e.g., to record scores on commonly used standardized tasks that could, with permission, be shared with different researchers). Next, we conducted a preliminary evaluation of a prototype Research Passport via usability testing in three ongoing research projects. Nine autistic participants without an ID provided feedback on the Research Passport (via a survey), as did three nonautistic researchers (via interviews). We found that the Research Passport (1) promoted positive participant-researcher relationships, (2) provided a structure and framework to support existing practices, and (3) needed to be adapted slightly to facilitate usability and manage expectations. Overall, the Research Passport was useful in promoting empathetic autism research. Further design and development of the Research Passport are warranted.

Lay summary

Why was this research developed?: Autistic adults taking part in research do not always have good experiences. An autistic member on our team thought that a Research Passport could help improve people's experiences. This idea was inspired by "passports" or "toolkits" that autistic people can use when visiting professionals such as doctors (so the doctor knows about the person and how to support them).What does the Research Passport do?: The Research Passport lets autistic people tell researchers about themselves before taking part in a research study. Autistic people can decide how much, or how little, they tell the researcher. Autistic and/or nonautistic researchers can use the Research Passport to try and make sure that their autistic participants have good experiences when taking part in research.How did the researchers evaluate the Research Passport?: First, nine autistic adults (who did not have an intellectual disability) and six autism researchers took part in group discussions. We asked what they thought about our Research Passport idea and what it should include. We made a Research Passport mock-up based on these discussions. Nine autistic participants who did not have an intellectual disability used the mock-up in one of three university research projects. Autistic participants completed a survey to tell us good and not-so-good things about the Research Passport. Also, we interviewed three researchers about using the Research Passport (asking what they liked and what could have been better).What were the findings?: Autistic adults and researchers involved in designing the Research Passport thought the Research Passport (1) could be useful but could not solve all problems in autism research, (2) needed to be suitable for many different people, and (3) could have many different benefits (e.g., collecting participants' scores on tests that researchers use a lot, so participants do not have to keep doing the same tests each time they take part in a new research study).Autistic adults and researchers used the Research Passport in ongoing studies and told us that it (1) led to good relationships between participants and researchers, (2) helped researchers make sure that the way they did their research was acceptable, and (3) was useful. However, participants need to be told what the Research Passport can/cannot help them with.What were the weaknesses of this project?: This study involved a small group of autistic adults and researchers, and the results may not be the same with autistic adults and researchers who have different needs. Also, participants said the Research Passport was not very easy to complete, and a bit long. We need to change the Research Passport so that a wider range of autistic people (like those with intellectual disability) can use it.What are the next steps?: The Research Passport needs to be professionally designed so it is easier to be used by a wider range of autistic people. A bigger evaluation of the Research Passport could allow us to test it with more participants and in more research studies.How will this work help autistic adults now or in the future?: Using the Research Passport could, with some changes and alongside other supports, improve the experience of autistic adults taking part in research.

In the physical to digital transition with friends - a story of performing inclusive research together no matter what life throws at you

BACKGROUND

As part of 'The Hub' project at Wellcome Collection, a team of eight co-researchers with learning disabilities alongside academics created an online survey to challenge public understanding of learning disabilities. Using creative and arts-based methods, co-researchers remotely co-analysed the survey results amid Covid-19 lockdown challenges. Here, we explore our unexpected 'transition' journey from the physical 'Hub' to the digital space.

METHODS

We organised 20 sessions at 'The Hub' and used audio/video/photo recordings to 'capture' key moments. With the lockdown, we ensured that every co-researcher had access to and support for digital technologies. Throughout 2020, we organized 28 Zoom meetings involving all co-researchers. In June, Lilly and Sue conducted Zoom interviews with the co-research team to reflect on our 'transition' journey. In this creative video-form submission accompanied by an accessible report, Lilly puts together a story of how we transitioned and felt throughout this process.

FINDINGS

We identify that trust and the social bonds established at 'The Hub' are the key components of our transition to the digital environment. There is the tension between longing for in-person contact and trying to make the most out of the situation to maintain these relationships. At the heart of this is the motivation to 'change the world' and the strive for social justice. Having time and opportunity to improve, and co-researchers' steady growth in confidence, are equally important.

CONCLUSIONS

The determination for maintaining friendships among co-researchers and the motivation to 'change the world' overcome Covid-19 related challenges in continuing co-research.

SUMMARY

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COVID-19, social isolation and the mental health of autistic people and their families: A qualitative study

LAY ABSTRACT

In this study, we show that autistic people and their families have found it very difficult to deal with the lockdowns during the COVID-19 pandemic. Autistic and non-autistic researchers spoke to 144 people, including 44 autistic adults, 84 parents of autistic children and 16 autistic young people (12-18 years old). We asked them about their everyday lives and mental health during lockdown. People told us that they enjoyed having fewer obligations and demands compared to pre-COVID-19 life. They felt that life was quieter and calmer. But people also told us again and again how much they missed meeting people in real life, especially their friends, and their therapists and support workers. People told us that their mental health suffered because they did not have contact with their friends and services. Importantly, many people (including researchers) think that autistic people do not want friends or to be around people. But our results show that is not true. Many autistic people do want friends and to be around other people. Some people's mental health has been damaged by not being able to see people during COVID-19. Autistic people need support in many areas of life so they can keep socialising and seeing their friends even through difficult times, like pandemics.

"It just fits my needs better": Autistic students and parents' experiences of learning from home during the early phase of the COVID-19 pandemic

BACKGROUND AND AIMS

The COVID-19 pandemic has caused unprecedented disruption to people's lives, especially for families, whose children have been taken out of schools during lockdown restrictions and required to learn from home. Little is known, however, about the perceived impact of the lockdown restrictions on the educational experiences of autistic children and young people - a group whose conventional schooling experiences are already often challenging. In this study, we sought to (1) understand these experiences from the perspectives of autistic young people and their parents, and (2) identify the underlying sources of positive experiences at this challenging time, in order to inform the ways in which autistic children might flourish at school in more normal times.

METHODS

Ninety-one Australian participants, including 16 autistic young people aged 12-18 years, 32 autistic parents and 43 non-autistic parents of autistic young people aged 3-18 years, took part in semi-structured interviews about their experiences of life during the initial phase of the COVID-19 pandemic. The interviews were subjected to reflexive, thematic analysis to identify themes and subthemes for each research question.

RESULTS

Overall, our participants initially found the transition to learning from home extremely challenging, with parents reporting that the support received from schools was far from adequate. After that initial period of transition, however, many autistic children reported flourishing at home both educationally and personally. For these children and families, we identified three key ingredients essential to this flourishing, including: (i) the importance of connected, trusting relationships ('people'); (ii) the sensory and social safety of home ('place'); and (iii) the flexibility to pace and structure learning to suit the individual child ('time').

CONCLUSIONS

While the initial COVID-19 lockdown presented many challenges to children learning at home, there were aspects of this otherwise-unsettling situation that enabled children to thrive and from which we can learn for the future.

IMPLICATIONS

These findings have important implications for understanding how and when autistic children might thrive in institutional educational settings once the pandemic subsides, focusing on the relationships between teachers and students, the nature of the physical learning environment and the need for greater flexibility in planning the school day.

"We have been magnified for years - Now you are under the microscope!": Co-researchers with Learning Disabilities Created an Online Survey to Challenge Public Understanding of Learning Disabilities

Public attitudes towards learning disabilities (LDs) are generally reported as positive, inclusive and empathetic. However, these findings do not reflect the lived experiences of people with LDs. To shed light on this disparity, a team of co-researchers with LDs created the first online survey to challenge public understanding of LDs, asking questions in ways that are important to them and represent how they see themselves. Here, we describe and evaluate the process of creating an accessible survey platform and an online survey in a research team consisting of academic and non-academic professionals with and without LDs or autism. Through this inclusive research process, the co-designed survey met the expectations of the co-researchers and was well-received by the initial survey respondents. We reflect on the co-researchers' perspectives following the study completion, and consider the difficulties and advantages we encountered deploying such approaches and their potential implications on future survey data analysis.

'People should be allowed to do what they like': Autistic adults' views and experiences of stimming

'Stereotyped or repetitive motor movements' are characterised as core features in the diagnosis of autism, yet many autistic adults (and the neurodiversity movement) have reclaimed them as 'stimming'. Supported by a growing body of scientific research, autistic adults argue that these behaviours may serve as useful coping mechanisms, yet little research has examined stimming from the perspective of autistic adults. Through interviews and focus groups, we asked 32 autistic adults to share their perceptions and experiences of stimming, including the reasons they stim, any value doing so may hold for them and their perceptions of others' reactions to stimming. Using thematic analysis, we identified two themes: stimming as (1) a self-regulatory mechanism and (2) lacking in social acceptance, but can become accepted through understanding. Autistic adults highlighted the importance of stimming as an adaptive mechanism that helps them to soothe or communicate intense emotions or thoughts and thus objected to treatment that aims to eliminate the behaviour.

"Life is Much More Difficult to Manage During Periods": Autistic Experiences of Menstruation

Although menarche and menstruation are perceived to be overwhelmingly negative events for developmentally-disabled women, women’s health issues remain under-researched in autism. Here, we conducted a preliminary investigation of the experiences of post-menarcheal autistic (n = 123) and non-autistic (n = 114) respondents to a brief online survey. Although autistic respondents reported many overlapping issues and experiences with non-autistic respondents, they also highlighted distinct—and sometimes-distressing—issues relating to menstruation, especially a cyclical amplification of autistic-related challenges, including sensory differences and difficulties with regulating emotion and behavior, which had a significant, negative impact on their lives. These initial findings call for systematic research on the potential causes, correlates and consequences of menstrual-related problems in autistic individuals—across the spectrum and the lifespan.

The Experiences of Late-diagnosed Women with Autism Spectrum Conditions: An Investigation of the Female Autism Phenotype

We used Framework Analysis to investigate the female autism phenotype and its impact upon the under-recognition of autism spectrum conditions (ASC) in girls and women. Fourteen women with ASC (aged 22–30 years) diagnosed in late adolescence or adulthood gave in-depth accounts of: ‘pretending to be normal’; of how their gender led various professionals to miss their ASC; and of conflicts between ASC and a traditional feminine identity. Experiences of sexual abuse were widespread in this sample, partially reflecting specific vulnerabilities from being a female with undiagnosed ASC. Training would improve teachers’ and clinicians’ recognition of ASC in females, so that timely identification can mitigate risks and promote wellbeing of girls and women on the autism spectrum.

Nuclear factor-kappa B pathways in Drosophila

The nuclear factor kappa B (NF-kappaB) pathways in Drosophila are multi-component pathways, as in vertebrates, that regulate the expression of many genes responsible for the formation of dorsal-ventral polarity in the early embryo, the innate immune response to infection with Gram- negative and positive bacteria and fungi, the cellular immune response and hematopoiesis. Overactivation of the fly pathway can result in developmental defects, overproliferation of hemocytes and the formation of melanotic tumors or nodules. The extracellular events leading to the maturation of the ligand for initiation of the Drosophila NF-kappaB pathway is not conserved between flies and vertebrates, but the Toll receptor and downstream events are remarkably similar. NF-kappaB proteins have been identified in mollusks, and arthropods such as horseshoe crabs and beetles, indicating that this pathway has been established more than 500 million years ago. The fly NF-kappaB pathways are less complex than those in vertebrates, with the involvement of fewer proteins, but they are, nonetheless, just as important as their vertebrate counterparts for the life of the fly.

Bicaudal-D is essential for egg chamber formation and cytoskeletal organization in drosophila oogenesis

Bicaudal-D (Bic-D) is required for the transport of determinant mRNAs and proteins to the presumptive oocyte, an essential step in the differentiation of the oocyte. Bic-D protein contains four well-defined heptad repeat domains characteristic of intermediate filament proteins. We characterized the ovarian phenotypes of females expressing mutant Bic-D proteins (Bic-D(H)) deleted for each of the heptad repeat domains. The altered migration of follicle cells we observe in mutant ovaries suggests that Bic-D functions in the germline and directs the inward migration of somatic follicle cells. In the germarium Bic-D is required for the organization of the egg chamber and the structural integrity of the oocyte and nurse cells. Examination of the polarized microtubule network in Bic-D(H) ovaries shows that Bic-D function is required for both the establishment of the polarized microtubule network and its maintenance throughout oogenesis. To explain the multiple functions suggested by the pleiotropic Bic-D phenotype, we propose that Bic-D protein could form itself a filamentous structure and represent an integral, essential part of the cytoskeleton.

Drosophila Lis1 is required for neuroblast proliferation, dendritic elaboration and axonal transport

Haplo-insufficiency of human Lis1 causes lissencephaly. Reduced Lis1 activity in both humans and mice results in a neuronal migration defect. Here we show that Drosophila Lis1 is highly expressed in the nervous system. Lis1 is essential for neuroblast proliferation and axonal transport, as shown by a mosaic analysis using a Lis1 null mutation. Moreover, it is cell-autonomously required for dendritic growth, branching and maturation. Analogous mosaic analysis shows that neurons containing a mutated cytoplasmic-dynein heavy chain (Dhc64C) exhibit phenotypes similar to Lis1 mutants. These results implicate Lis1 as a regulator of the microtubule cytoskeleton and show that it is important for diverse physiological functions in the nervous system.

The shut-down gene of Drosophila melanogaster encodes a novel FK506-binding protein essential for the formation of germline cysts during oogenesis

In Drosophila melanogaster, the process of oogenesis is initiated with the asymmetric division of a germline stem cell. This division results in the self-renewal of the stem cell and the generation of a daughter cell that undergoes four successive mitotic divisions to produce a germline cyst of 16 cells. Here, we show that shut-down is essential for the normal function of the germline stem cells. Analysis of weak loss-of-function alleles confirms that shut-down is also required at later stages of oogenesis. Clonal analysis indicates that shut-down functions autonomously in the germline. Using a positional cloning approach, we have isolated the shut-down gene. Consistent with its function, the RNA and protein are strongly expressed in the germline stem cells and in 16-cell cysts. The RNA is also present in the germ cells throughout embryogenesis. shut-down encodes a novel Drosophila protein similar to the heat-shock protein-binding immunophilins. Like immunophilins, Shut-down contains an FK506-binding protein domain and a tetratricopeptide repeat. In plants, high-molecular-weight immunophilins have been shown to regulate cell divisions in the root meristem in response to extracellular signals. Our results suggest that shut-down may regulate germ cell divisions in the germarium.

Cactin, a conserved protein that interacts with the Drosophila IkappaB protein cactus and modulates its function

Rel transcription factors function in flies and vertebrates in immunity and development. Although Rel proteins regulate diverse processes, the control of their function is conserved. In a two-hybrid screen for additional components of the pathway using the Drosophila I-kappaB protein Cactus as a bait, we isolated a novel coiled-coil protein with N-terminal Arg-Asp (RD)- like motifs that we call Cactin. Like the other components of this pathway, Cactin is evolutionarily conserved. Over-expression of cactin in a cactus(A2) heterozygous background results in the enhancement of the cactus phenotype. Both the embryonic lethality and ventralization are strongly increased, suggesting that cactin functions in the Rel pathway controlling the formation of dorsal-ventral embryonic polarity.

The Drosophila shark tyrosine kinase is required for embryonic dorsal closure

Dorsal closure (DC) in the Drosophila embryo requires the coordinated interaction of two different functional domains of the epidermal cell layer-the leading edge (LE) and the lateral epidermis. In response to activation of a conserved c-Jun amino-terminal kinase (JNK) signaling module, the dorsal-most layer of cells, which constitute the LE of the stretching epithelial sheet, secrete Dpp, a member of the TGFbeta superfamily. Dpp and other LE cell-derived signaling molecules stimulate the bilateral dorsal elongation of cells of the dorsolateral epidermis over the underlaying amnioserosa and the eventual fusion of their LEs along the dorsal midline. We have found that flies bearing a Shark tyrosine kinase gene mutation, shark(1), exhibit a DC-defective phenotype. Dpp fails to be expressed in shark(1) mutant LE cells. Consistent with these observations, epidermal-specific reconstitution of shark function or overexpression of an activated form of c-Jun in the shark(1) mutant background, rescues the DC defect. Thus, Shark regulates the JNK signaling pathway leading to Dpp expression in LE cells. Furthermore, constitutive activation of the Dpp pathway throughout the epidermis fails to rescue the shark(1) DC defect, suggesting that Shark may function in additional pathways in the LE and/or lateral epithelium.

Functional domains of the Drosophila bicaudal-D protein

The localization of oocyte-specific determinants in the form of mRNAs to the pro-oocyte is essential for the establishment of oocyte identity. Localization of the Bicaudal-D (Bic-D) protein to the presumptive oocyte is required for the accumulation of Bic-D and other mRNAs to the pro-oocyte. The Bic-D protein contains four well-defined heptad repeat domains characteristic of intermediate filament proteins, and several of the mutations in Bic-D map to these conserved domains. We have undertaken a structure-function analysis of Bic-D by testing the function of mutant Bic-D transgenes (Bic-D(H)) deleted for each of the heptad repeat domains in a Bic-D null background. Our transgenic studies indicate that only the C-terminal heptad repeat deletion results in a protein that has lost zygotic and ovarian functions. The three other deletions result in proteins with full zygotic function, but with affected ovarian function. The functional importance of each domain is well correlated with its conservation in evolution. The analysis of females heterozygous for Bic-D(H) and the existing alleles Bic-D(PA66) or Bic-D(R26) reveals that Bic-D(R26) as well as some of Bic-D(H) transgenes have antimorphic effects. The yeast two-hybrid interaction assay shows that Bic-D forms homodimers. Furthermore, we found that Bic-D exists as a multimeric protein complex consisting of Egl and at least two Bic-D monomers.

Cactus-independent regulation of Dorsal nuclear import by the ventral signal

Rel-family transcription factors function in a variety of biological processes, including development and immunity. During early Drosophila development, the Toll-Cactus-Dorsal pathway regulates the establishment of the embryonic dorsoventral axis. The last step in this pathway is the graded nuclear import of the Rel protein Dorsal. Dorsal is retained in the cytoplasm by the IkappaB-family protein Cactus. Phosphorylation of both Dorsal and Cactus is regulated by a Toll-receptor-dependent ventral signal relayed by the Tube and Pelle proteins. Phosphorylation of Cactus leads to its degradation and to the release of Dorsal to form a ventral-to-dorsal nuclear Dorsal gradient. To understand how the ventral signal regulates the nuclear import and activity of Dorsal, we deleted its conserved nuclear localization signal (NLS). The truncated protein remained in the cytoplasm and could antagonize the function of wild-type Dorsal, suggesting that Dorsal forms a dimer in the cytoplasm. Further, the nuclear import of a mutant Dorsal protein that failed to interact with Cactus was still regulated by the ventral signal. Our results are consistent with a model in which ventral signal-dependent modification of both Cactus and Dorsal is required for the graded nuclear import of Dorsal.

flex, an X-linked female-lethal mutation in Drosophila melanogaster controls the expression of Sex-lethal

The Sex-lethal (Sxl) gene is required in Drosophila females for sexual differentiation of the soma, for gem cell differentiation and dosage compensation. We have isolated three new alleles of female-lethal-on-X (flex), an X-linked female-lethal mutation and have characterized its function in sex determination. SXL protein is missing in flex/flex embryos, however transcription from both Sxl(Pe), the early Sxl promoter and Sxl(Pm), the late maintenance promoter, is normal in flex homozygotes. In flex/flex embryos, Sxl mRNA is spliced in the male mode. Analysis of flex germline clones shows that it also functions in oogenesis, but in contrast to Sxl mutants that show an early arrest tumorous phenotype, flex mutant egg chambers develop to stage 10. In flex ovarian clones, Sxl RNA is also spliced in the male form. Hence, flex is a sex-specific regulator of Sxl functioning in both the soma and the germline. Genetic interaction studies show that flex does not enhance female lethality of Sxl loss-of-function alleles but it rescues the male-specific lethality of both of the gain-of-function Sxl mutations, Sxl(M1)and Sxl(M4.) In contrast to mutations in splicing regulators of Sxl, the female lethality of flex is not rescued by either Sxl(M1)or Sxl(M4). Based on these observations, we propose that flex regulates Sxl at a post-splicing stage and regulates either its translation or the stability of the SXL protein.

Lis1, the Drosophila homolog of a human lissencephaly disease gene, is required for germline cell division and oocyte differentiation

Lissencephaly is a severe congenital brain malformation resulting from incomplete neuronal migration. One causal gene, LIS1, is homologous to nudF, a gene required for nuclear migration in A. nidulans. We have characterized the Drosophila homolog of LIS1 (Lis1) and show that Lis1 is essential for fly development. Analysis of ovarian Lis1 mutant clones demonstrates that Lis1 is required in the germline for synchronized germline cell division, fusome integrity and oocyte differentiation. Abnormal packaging of the cysts was observed in Lis1 mutant clones. Our results indicate that LIS1 is important for cell division and differentiation and the function of the membrane cytoskeleton. They support the notion that LIS1 functions with the dynein complex to regulate nuclear migration or cell migration.

A mosaic analysis in Drosophila fat body cells of the control of antimicrobial peptide genes by the Rel proteins Dorsal and DIF

Expression of the gene encoding the antifungal peptide Drosomycin in Drosophila adults is controlled by the Toll signaling pathway. The Rel proteins Dorsal and DIF (Dorsal-related immunity factor) are possible candidates for the transactivating protein in the Toll pathway that directly regulates the drosomycin gene. We have examined the requirement of Dorsal and DIF for drosomycin expression in larval fat body cells, the predominant immune-responsive tissue, using the yeast site-specific flp/FRT recombination system to generate cell clones homozygous for a deficiency uncovering both the dorsal and the dif genes. Here we show that in the absence of both genes, the immune-inducibility of drosomycin is lost but can be rescued by overexpression of either dorsal or dif under the control of a heat-shock promoter. This result suggests a functional redundancy between both Rel proteins in the control of drosomycin gene expression in the larvae of Drosophila. Interestingly, the gene encoding the antibacterial peptide Diptericin remains fully inducible in the absence of the dorsal and dif genes. Finally, we have used fat body cell clones homozygous for various mutations to show that a linear activation cascade Spaetzle--> Toll-->Cactus-->Dorsal/DIF leads to the induction of the drosomycin gene in larval fat body cells.

Nuclear import of the Drosophila Rel protein Dorsal is regulated by phosphorylation

In Drosophila, dorsal-ventral polarity is determined by a maternally encoded signal transduction pathway that culminates in the graded nuclear localization of the Rel protein, Dorsal. Dorsal is retained in the cytoplasm by the IkappaB protein, Cactus. Signal-dependent phosphorylation of Cactus results in the degradation of Cactus and the nuclear targeting of Dorsal. We present an in-depth study of the functional importance of Dorsal phosphorylation. We find that Dorsal is phosphorylated by the ventral signal while associated with Cactus, and that Dorsal phosphorylation is essential for its nuclear import. In vivo phospholabeling of Dorsal is limited to serine residues in both ovaries and early embryos. A protein bearing mutations in six conserved serines abolishes Dorsal activity, is constitutively cytoplasmic, and appears to eliminate Dorsal phosphorylation, but still interacts with Cactus. Two individual serine-to-alanine mutations produce unexpected results. In a wild-type signaling background, a mutation in the highly conserved PKA site (S312) produces only a weak loss-of-function; however, it completely destabilizes the protein in a cactus mutant background. Significantly, the phosphorylation of another completely conserved serine (S317) regulates the high level of nuclear import found in ventral cells. We conclude that the formation of a wild-type Dorsal nuclear gradient requires the phosphorylation of both Cactus and Dorsal. The strong conservation of the serines suggests that phosphorylation of other Rel proteins is essential for their proper nuclear targeting.

A multimeric complex and the nuclear targeting of the Drosophila Rel protein Dorsal

The intracellular part of the Rel signal transduction pathway in Drosophila is encoded by Toll, tube, pelle, dorsal, and cactus, and it functions to form the dorsal-ventral axis in the Drosophila embryo. Upon activation of the transmembrane receptor Toll, Dorsal dissociates from its cytoplasmic inhibitor Cactus and enters the nucleus. Tube and Pelle are required to relay the signal from Toll to the Dorsal-Cactus complex. In a yeast two-hybrid assay, we found that both Tube and Pelle interact with Dorsal. We confirmed these interactions in an in vitro binding assay. Tube interacts with Dorsal via its C-terminal domain, whereas full-length Pelle is required for Dorsal binding. Tube and Pelle bind Dorsal in the N-terminal domain 1 of the Dorsal Rel homology region rather than at the Cactus binding site. Domain 1 has been found to be necessary for Dorsal nuclear targeting. Genetic experiments indicate that Tube-Dorsal interaction is necessary for normal signal transduction. We propose a model in which Tube, Pelle, Cactus, and Dorsal form a multimeric complex that represents an essential aspect of signal transduction.

Axon patterning requires DN-cadherin, a novel neuronal adhesion receptor, in the Drosophila embryonic CNS

We identified DN-cadherin, a novel Drosophila cadherin that is expressed in axons and in the mesoderm. Although DN-cadherin has diverged from vertebrate classic cadherins in terms of its extracellular structure, it still can form a complex with catenins and induce cell aggregation, as do the vertebrate molecules. Loss-of-function mutations of the gene resulted in either embryonic lethality or uncoordinated locomotion of adults. In the central nervous system of null mutant embryos, subsets of ipsilateral axons displayed a variety of aberrant trajectories including failure of position shifts, defective bundling, and errors in directional migration of growth cones. These results suggest that processes of axon patterning critically depend on DN-cadherin-mediated axon-axon interactions.

The dorsoventral signal transduction pathway and the Rel-like transcription factors in Drosophila

Embryonic dorsoventral polarity in Drosophila melanogaster is determined by a maternally-encoded signal transduction pathway whose effector molecule is the Rel transcription factor, Dorsal. The activity of this signal transduction pathway gives rise to a ventral-to-dorsal nuclear gradient of Dorsal, which then activates and represses several zygotic target genes in distinct domains. The dorsoventral system represents the best characterized of the Rel pathways. Its components have now been ordered and their biochemical roles are becoming clearer. Key components of the dorsoventral pathway show striking similarity to those involved with the regulation of vertebrate Rel family members. Additional Drosophila Rel family members have been identified and implicated in the innate immune response. The dorsoventral pathway is also remarkably conserved in this response. This conservation underscores the relevance of the dorsoventral system for our understanding of the entire Rel family.

Regulated nuclear import of the Drosophila rel protein dorsal: structure-function analysis

The formation of a gradient of nuclear Dorsal protein in the early Drosophila embryo is the last step in a maternally encoded dorsal-ventral signal transduction pathway. This gradient is formed in response to a ventral signal, which leads to the dissociation of cytoplasmic Dorsal from the I kappa B homolog Cactus. Free Dorsal is then targeted to the nucleus. Dorsal is a Rel-family transcription factor. Signal-dependent nuclear localization characterizes the regulation of Rel proteins. In order to identify regions of Dorsal that are essential for its homodimerization, nuclear targeting, and interaction with Cactus, we have performed an in vivo structure-function analysis. Our results show that all these functions are carried out by regions within the conserved Rel-homology region of Dorsal. The C-terminal divergent half of Dorsal is dispensable for its selective nuclear import. A basic stretch of 6 amino acids at the C terminus of the Rel-homology region is necessary for nuclear localization. This nuclear localization signal is not required for Cactus binding. Removal of the N-terminal 40 amino acids abolished the nuclear import of Dorsal, uncovering a potentially novel function for this highly conserved region.

The anterior-posterior and dorsal-ventral axes have a common origin in Drosophila melanogaster

The mechanisms governing anterior-posterior and dorsal-ventral polarity in Drosophila melanogaster had previously been considered as independent processes. However, two papers(1,2) now reveal that both axes are initiated during oogenesis by the same pathway, and also clearly demonstrate that one is dependent on the other.

Functional analysis and regulation of nuclear import of dorsal during the immune response in Drosophila

In addition to its function in embryonic development, the NF-kappa B/rel-related gene dorsal (dl) of Drosophila is expressed in larval and adult fat body where its RNA expression is enhanced upon injury. Injury also leads to a rapid nuclear translocation of dl from the cytoplasm in fat body cells. Here we present data which strongly suggest that the nuclear localization of dl during the immune response is controlled by the Toll signaling pathway, comprising gene products that participate in the intracellular part of the embryonic dorsoventral pathway. We also report that in mutants such as Toll or cactus, which exhibit melanotic tumor phenotypes, dl is constitutively nuclear. Together, these results point to a potential link between the Toll signaling pathway and melanotic tumor induction. Although dl has been shown previously to bind to kappa B-related motifs within the promoter of the antibacterial peptide coding gene diptericin, we find that injury-induced expression of diptericin can occur in the absence of dl. Furthermore, the melanotic tumor phenotype of Toll and cactus is not dl dependent. These data underline the complexity of the Drosophila immune response. Finally, we observed that like other rel proteins, dl can control the level of its own transcription.

Dissociation of the dorsal-cactus complex and phosphorylation of the dorsal protein correlate with the nuclear localization of dorsal

The formation of dorsal-ventral polarity in Drosophila requires the asymmetric nuclear localization of the dorsal protein along the D/V axis. This process is regulated by the action of the dorsal group genes and cactus. We show that dorsal and cactus are both phosphoproteins that form a stable cytoplasmic complex, and that the cactus protein is stabilized by its interaction with dorsal. The dorsal-cactus complex dissociates when dorsal is targeted to the nucleus. While the phosphorylation of cactus remains apparently unchanged during early embryogenesis, the phosphorylation state of dorsal correlates with its release from cactus and with its nuclear localization. This differential phosphorylation event is regulated by the dorsal group pathway.

Dorsal-ventral polarity in the Drosophila embryo

Embryonic dorsal-ventral polarity in Drosophila is established through a series of successive steps and requires the functions of both maternal and zygotic genes. The graded distribution of the transcription factor dorsal in blastoderm nuclei represents the transition from the maternal to the zygotic program. This results in the activation of specific zygotic genes that act to create the regional pattern along this axis.

Homeostatic balance between dorsal and cactus proteins in the Drosophila embryo

The maternal-effect gene dorsal encodes the ventral morphogen that is essential for elaboration of ventral and ventrolateral fates in the Drosophila embryo. Dorsal belongs to the rel family of transcription factors and controls asymmetric expression of zygotic genes along the dorsoventral axis. The dorsal protein is cytoplasmic in early embryos, possibly because of a direct interaction with cactus. In response to a ventral signal, dorsal protein becomes partitioned into nuclei of cleavage-stage syncytial blastoderms such that the ventral nuclei have the maximum amount of dorsal protein, and the lateral and dorsal nuclei have progressively less protein. Here we show that transgenic flies containing the dorsal cDNA, which is driven by the constitutively active hsp83 promoter, exhibits rescue of the dorsal- phenotype. Transformed lines were used to increase the level of dorsal protein. Females with dorsal levels roughly twice that of wild-type produced normal embryos, while a higher level of dorsal protein resulted in phenotypes similar to those observed for loss-of-function cactus mutations. By manipulating the cactus gene dose, we found that in contrast to a dorsal/cactus ratio of 2.5 which resulted in fully penetrant weak ventralization, a cactus/dorsal ratio of 3.0 was acceptable by the system. By manipulating dorsal levels in different cactus and dorsal group mutant backgrounds, we found that the relative amounts of ventral signal to that of the dorsal-cactus complex is important for the elaboration of the normal dorsoventral pattern. We propose that in a wild-type embryo, the activities of dorsal and cactus are not independently regulated; excess cactus activity is deployed only if a higher level of dorsal protein is available. Based on these results we discuss how the ventral signal interacts with the dorsal-cactus complex, thus forming a gradient of nuclear dorsal protein.

In vivo self-association of the Drosophila rel-protein dorsal

The Drosophila morphogen dorsal, KBF1, NF-kappa B, and the proto-oncogene c-rel belong to the rel family of transcription factors whose function is regulated post-translationally by selective nuclear import. In the early Drosophila embryo, dorsal protein is proposed to be retained in the cytoplasm through its interaction with cactus protein. The maternal dorsal group genes constitute a signal transduction pathway, which results in targeting cytoplasmic dorsal protein into the nuclei of the syncytial blastoderm embryo, in a ventral-to-dorsal gradient. The asymmetric transcriptional regulation of zygotic genes along the dorsoventral axis by the dorsal morphogen gradient establishes embryonic dorsoventral polarity. In the lymphocytes, the functional equivalent of cactus is I kappa B, which appears to retain NF-kappa B in the cytoplasm. This retention is relieved by extracellular signals in tissue culture. NF-kappa B and rel proteins each are known to function as oligomeric complexes. Here we present genetic and biochemical evidence for the existence and functional importance of an oligomeric dorsal complex in vivo.

Requirement for phosphorylation and localization of the Bicaudal-D protein in Drosophila oocyte differentiation

In the Drosophila female the product of the germline stem cell, the cystoblast, gives rise to 16 interconnected cystocytes. One of them differentiates into the oocyte, while the 15 others become polyploid nurse cells. Bic-D is required for the differentiation of an oocyte and hence for fertility. Recessive mutations in Bic-D block the oocyte-specific accumulation of its own and other RNAs. Based on its properties and distribution, the Bic-D protein appears to be a component of a cytoskeletal transport or anchoring system. Additional results suggest that the phosphorylation of the Bic-D protein is essential for its accumulation in the pro-oocyte and that this process leads to the gradual localization to the pro-oocyte of factors required for oocyte differentiation.

Dorsoventral pattern formation in Drosophila: signal transduction and nuclear targeting

The maternal determinants of dorsoventral polarity of the Drosophila embryo are derived from somatic and germ-line components of the egg chamber. During oogenesis, asymmetry seems to be established by a signal transduction process. This process is thought to provide the developing embryo with a ventral signal responsible for determining the embryonic axis. Through a set of interactions that may involve signal transduction and proteolytic cascade events, positional information is generated in the form of a graded distribution of dorsal protein in blastoderm nuclei. Different levels of dorsal protein result in asymmetric expression of zygotic genes that ultimately specify cell fate.