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Addo IY, Acquah E, Nyarko SH, Dickson KS, Boateng ENK, Ayebeng C. Exposure to pro-tobacco and anti-tobacco media messages and events and smoking behaviour among adolescents in Gambia. BMC Public Health 2024; 24:1041. [PMID: 38622588 PMCID: PMC11017583 DOI: 10.1186/s12889-024-18543-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/07/2024] [Indexed: 04/17/2024] Open
Abstract
BACKGROUND Despite the widespread prevalence of adolescent smoking in Gambia, a West African country, there is limited research exploring the relationships between exposure to pro-tobacco and anti-tobacco media messages and events and smoking behaviour among young people. This study investigates the interplay of these exposures and smoking behaviour among 11-17-year-old adolescents in Gambia. METHODS Secondary data analysis was conducted using the 2017 Gambia Global Youth and Tobacco Survey (GYTS), which included a total of 9,127 respondents. Descriptive and inferential analyses, including proportions, Pearson's chi-squared tests, and multivariable logistic regression models, were employed to estimate adjusted odds ratios (aOR) with 95% confidence intervals (CI). RESULTS The final model revealed significant associations between exposure to anti-tobacco media messages and events and smoking behaviour. Adolescents exposed to anti-tobacco media messages had a 29% increased odds of smoking (aOR 1.29,CI = 1.08,1.53) compared to those unexposed, while exposure to anti-tobacco media events showed a 31% increased odds (aOR 1.31,CI = 1.09,1.59) compared to those unexposed. Exposure to pro-tobacco messages, such as witnessing tobacco use on TV (aOR 1.41, CI = 1.17,1.69) and owning objects with tobacco brand logos (aOR 1.49,CI = 1.19,1.86), was associated with higher odds of smoking. Covariates, including sex, age, and exposure to smoking behaviour by significant others, also demonstrated associations with smoking behaviour. Notably, male respondents showed significantly higher odds of smoking (aOR = 4.01,CI = 3.28,4.89) compared to females. Respondents aged 15 years and older had increased odds of smoking (aOR = 1.47,CI = 1.22,1.76) compared to those below 15 years old. Those whose fathers smoke displayed higher odds of smoking (aOR = 1.35, CI = 1.04,1.76) compared to individuals with non-smoking parents. Additionally, those whose closest friends smoke showed remarkably higher odds of smoking (aOR = 2.87,CI = 2.37, 3.48) compared to those without such influence. CONCLUSION This study underscores the significant impact of exposure to both anti-tobacco and pro-tobacco media messages and events on smoking behaviour among adolescents in Gambia. However, pro-tobacco messages had a greater influence on smoking prevalence than anti-tobacco messages and events. Understanding these associations is crucial for devising effective public health interventions aimed at reducing tobacco use in this population.
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Affiliation(s)
- Isaac Yeboah Addo
- Concord Clinical School, University of Sydney, Sydney, Australia
- Centre for Social Research in Health, The University of New South Wales, Sydney, Australia
| | - Evelyn Acquah
- Centre for Health Policy and Implementation Research, Institute of Health Research, University of Health, and Allied Sciences, Ho, Ghana
| | - Samuel H Nyarko
- Department of Epidemiology, Human Genetics & Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, USA
| | - Kwamena S Dickson
- Department of Population and Health, University of Cape Coast, Cape Coast, Ghana
| | - Ebenezer N K Boateng
- Department of Geography and Regional Planning, University of Cape Coast, Cape Coast, Ghana
| | - Castro Ayebeng
- Department of Population and Health, University of Cape Coast, Cape Coast, Ghana.
- Department of Research and Advocacy, Challenging Heights, Winneba, Ghana.
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Nyarko SH, Addo IY, Ayebeng C, Dickson KS, Acquah E. Mediating effects of hypertension in association between household wealth disparities and diabetes among women of reproductive age: analysis of eight countries in sub-Saharan Africa. Int Health 2024:ihae013. [PMID: 38321706 DOI: 10.1093/inthealth/ihae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 12/19/2023] [Accepted: 01/15/2024] [Indexed: 02/08/2024] Open
Abstract
BACKGROUND Diabetes prevalence appears to be increasing in low- and middle-income countries, yet little is known about how hypertension status mediates the association between household wealth and diabetes. This study examined the mediation effects of hypertension in associations between household wealth and diabetes in eight sub-Saharan African (SSA) countries. METHODS This is a cross-sectional study of 71 577 women from recent Demographic and Health Surveys for eight SSA countries. Sample-weighted logistic regression and causal mediation analyses were conducted. RESULTS Of the 71 577 women, 1.1% (782) reported ever being diagnosed with diabetes. Women with diabetes were more likely to have hypertension compared with those without diabetes (54.9% vs 9.9%). The odds of diabetes were significantly higher among women with hypertension (adjusted odds ratio [OR] 5.71 [95% confidence interval {CI} 4.62 to 7.05]) and women from rich households (adjusted OR 1.65 [95% CI 1.23 to 2.22]) compared with their respective counterparts. Hypertension status mediated 27.4% of the association between household wealth and diabetes status. CONCLUSIONS Hypertension status partly contributes to the associations between household wealth disparities and diabetes status among women in the selected countries. Further research and targeted interventions are needed to explore specific mechanisms and confounding factors related to household wealth disparities, hypertension status and diabetes prevalence in this population.
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Affiliation(s)
- Samuel H Nyarko
- Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
| | - Isaac Y Addo
- Centre for Social Research in Health, University of New South Wales, Sydney, NSW, Australia
| | - Castro Ayebeng
- Department of Population and Health, University of Cape Coast, Cape Coast, Ghana
- Department of Research and Advocacy, Challenging Heights, Winneba, Ghana
| | - Kwamena S Dickson
- Department of Population and Health, University of Cape Coast, Cape Coast, Ghana
| | - Evelyn Acquah
- Centre for Health Policy and Implementation Research, Institute of Health Research, University of Health and Allied Sciences, Ho, Ghana
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Nyarko SH, Boateng ENK, Dickson KS, Adzrago D, Addo IY, Acquah E, Ayebeng C. Geospatial disparities and predictors of anaemia among pregnant women in Sub-Saharan Africa. BMC Pregnancy Childbirth 2023; 23:743. [PMID: 37864203 PMCID: PMC10588187 DOI: 10.1186/s12884-023-06008-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/19/2023] [Indexed: 10/22/2023] Open
Abstract
BACKGROUND Anaemia has become a major public health concern among women in Sub-Saharan Africa (SSA). However, little is known about the spatial disparities in anaemia prevalence and their associated factors among pregnant women in the region. This study analysed the spatial disparities in anaemia and their associated factors among pregnant women in rural and urban settings in SSA. METHODS This is a secondary analysis of the most recent demographic and health surveys of 26 countries in SSA. Spatial autocorrelation and hotspot assessment were conducted, while a multivariate logistic regression model was used to identify demographic factors associated with anaemia. RESULTS Anaemia was reported among ~50% of pregnant women in urban and rural areas of SSA. The hotspot analysis identified the West African sub-region as having a higher concentration of anaemia cases in rural settings. In urban areas, the odds of anaemia were significantly higher among pregnant women in their second trimester (Adjusted OR = 2.39, CI = 1.99, 2.76). On the other hand, pregnant women in their third trimester (Adjusted OR = 1.98, CI = 1.77, 2.22) and those who had taken intestinal parasite drugs (Adjusted OR = 1.12 CI = 1.02, 1.23) had a higher likelihood of having anaemia in rural areas. Pregnant women aged 35-39 years (Adjusted OR = 0.52, CI = 0.33, 0.81) and those aged 40-44 years (Adjusted OR = 0.69, CI = 0.50, 0.95) had a lesser likelihood of having anaemia compared to women aged 15-19 years in urban and rural areas respectively. Compared to Congo DR, Benin (OR = 2.22, CI = 1.51, 3.28) and Mali (OR = 3.71, CI = 2.73, 5.05) had higher odds of anaemia in urban and rural areas respectively. CONCLUSIONS Spatial disparities in anaemia persist among pregnant women in rural and urban settings in SSA. Prevailing spatial variations in anaemia may be addressed by specialised interventions considering the contextual residential settings and socio-economic factors highlighted in this study.
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Affiliation(s)
- Samuel H Nyarko
- Department of Epidemiology, Human Genetics & Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - Ebenezer N K Boateng
- Department of Geography and Regional Planning, University of Cape Coast, Cape Coast, Ghana
| | - Kwamena S Dickson
- Department of Population and Health, University of Cape Coast, Cape Coast, Ghana
| | - David Adzrago
- Center for Health Promotion and Prevention Research (CHPPR), School of Public Health, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - Isaac Y Addo
- Centre for Social Research in Health, The University of New South Wales, Sydney, Australia
| | - Evelyn Acquah
- Centre for Health Policy and Implementation Research, Institute of Health Research, University of Health, and Allied Sciences, Ho, Ghana
| | - Castro Ayebeng
- Department of Population and Health, University of Cape Coast, Cape Coast, Ghana.
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Dickson KS, Boateng ENK, Adzrago D, Addo IY, Acquah E, Nyarko SH. Silent suffering: unveiling factors associated with women's inability to seek help for intimate partner violence in sub-Saharan Africa (SSA). Reprod Health 2023; 20:110. [PMID: 37496013 PMCID: PMC10373244 DOI: 10.1186/s12978-023-01651-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 07/14/2023] [Indexed: 07/28/2023] Open
Abstract
BACKGROUND Evidence shows that intimate partner violence (IPV) occurs more frequently in sub-Saharan Africa (SSA) than in other regions of the world. However, limited empirical studies exist on the help-seeking behaviour of women who had experienced IPV in SSA. This study aimed to examine the help-seeking behaviour of women who had experienced IPV in SSA and the factors associated with their inability to seek help after experiencing IPV. METHODS This is a quantitative study based on data from the latest demographic and health surveys (DHS) of 24 SSA countries. A sample of 53,446 women aged 15-49 years was included in the study. Associations between women's background characteristics and their help-seeking behaviour after experiencing IPV were examined using proportions and multivariate logistic regression models. RESULTS Overall, 60.7% of the sample did not seek help after experiencing IPV. Women's inability to seek help for IPV was highest in Mali (80.4%) and lowest in Tanzania (43.1%). Women's level of education, wealth status, marital status, age, occupation, and country of residence had significant associations with 'not seeking help' for any type of IPV. Those who experienced generational violence (AOR = 1.26, CI = 1.19, 1.33) and those who justified wife-beating (AOR = 1.09, CI = 1.07, 1.15) had higher odds of not seeking help for any type of IPV compared to those who did not experience generational violence or did not justify wife beating. Women who experienced emotional violence (AOR = 0.53, CI = 0.51, 0.55) and physical violence (AOR = 0.74, CI = 0.70, 0.76) had lower odds of not seeking help for any type of IPV compared to their counterparts who did not experience these types of violence. CONCLUSION Women's inability to seek help for IPV is common in many SSA countries. This study shows that several socio-demographic factors, such as women's age, educational levels, wealth status, and marital status are associated with their inability to seek help for IPV. Additionally, women's justification of wife beating and experience of generational abuse are strongly associated with their inability to seek help for IPV. These factors need to be considered critically in IPV interventions in SSA.
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Affiliation(s)
- Kwamena S Dickson
- Department of Population and Health, University of Cape Coast, Cape Coast, Ghana
| | - Ebenezer N K Boateng
- Department of Geography and Regional Planning, University of Cape Coast, Cape Coast, Ghana.
| | - David Adzrago
- Center for Health Promotion and Prevention Research, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Isaac Y Addo
- Centre for Social Research in Health, The University of New South Wales, Sydney, Australia
| | - Evelyn Acquah
- Centre for Health Policy and Implementation Research, Institute of Health Research, University of Health, and Allied Sciences, Ho, Ghana
| | - Samuel H Nyarko
- Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC, USA
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Addo IY, Acquah E, Ayebeng C, Dickson KS. Influence of distance to health facilities on clinical breast cancer screening behaviour among women in five sub-Saharan African countries. BMC Public Health 2023; 23:915. [PMID: 37208657 DOI: 10.1186/s12889-023-15782-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 04/28/2023] [Indexed: 05/21/2023] Open
Abstract
BACKGROUND Regular breast screening is one of the most effective ways to detect early signs of breast cancer but travel distance to cancer-diagnostic facilities can affect breast screening attendance. Yet, limited studies have examined the impact of distance to cancer-diagnostic facilities on clinical breast screening behaviour among women in sub-Saharan Africa (SSA). This study examined the influence of travel distance to a health facility on clinical breast screening behaviour in five SSA countries: Namibia, Burkina Faso, Cote D'Ivoire, Kenya, and Lesotho. The study further assessed variations in clinical breast screening behaviour across diverse socio-demographic characteristics of women. METHODS A sample of 45,945 women was drawn from the most recent Demographic and Health Surveys (DHS) for the included countries. The DHS uses 2-stage stratified cluster sampling to select nationally representative samples of women (15-49) and men (15-64) via a cross-sectional design. Proportions and binary logistic regression were used to examine associations between the women's socio-demographic characteristics and breast screening attendance. RESULTS The overall proportion of survey participants who underwent clinical breast cancer screening was 16.3%. Travel distance to a health facility had a significant (p < 0.001) impact on clinical breast screening behaviour as 18.5% of participants who self-reported distance as "not a big problem" attended clinical breast screening compared to 10.8% who self-reported distance as "a big problem". The study further found that various socio-demographic factors were significantly associated with breast cancer screening uptake, including age, education level, media exposure, wealth status, parity, contraceptive use, health insurance coverage, and marital status. The multivariate analysis controlling for other factors confirmed the strong association between distance to health facilities and screening uptake. CONCLUSIONS The study found that travel distance is a significant factor affecting clinical breast screening attendance among women in the selected SSA countries. Furthermore, the likelihood of breast screening attendance varied depending on different women's characteristics. It is crucial to prioritise breast screening interventions, particularly among the disadvantaged women identified in this study, to achieve maximum public health benefits.
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Affiliation(s)
- Isaac Y Addo
- Centre for Social Research in Health, The University of New South Wales, Sydney, Australia
| | - Evelyn Acquah
- Centre for Health Policy and Implementation Research, Institute of Health Research, University of Health and Allied Sciences, Ho, Ghana
| | - Castro Ayebeng
- Department of Population and Health, University of Cape Coast, Cape Coast, Ghana.
| | - Kwamena S Dickson
- Department of Population and Health, University of Cape Coast, Cape Coast, Ghana
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Ameyaw EK, Adde KS, Paintsil JA, Dickson KS, Oladimeji O, Yaya S. Health facility delivery and early initiation of breastfeeding: Cross-sectional survey of 11 sub-Saharan African countries. Health Sci Rep 2023; 6:e1263. [PMID: 37181665 PMCID: PMC10173260 DOI: 10.1002/hsr2.1263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 04/20/2023] [Accepted: 05/01/2023] [Indexed: 05/16/2023] Open
Abstract
Background and Aims Early initiation of breastfeeding (EIB) remains one of the promising interventions for preventing neonatal and child deaths. EIB is positively associated with healthcare delivery or childbirth. Meanwhile, no study in sub-Saharan Africa (SSA) appears to have investigated the relationship between health facility delivery and EIB; thus, we assessed the correlation between health facility delivery and EIB. Methods We used data from the Demographic and Health Survey (DHS) of 64,506 women from 11 SSA countries. The outcome variable was whether the respondent had early breastfeeding or not. Two logistic regression models were used in the inferential analysis. With a 95% confidence interval (CI), the adjusted odds ratios (aORs) for each variable were calculated. The data set was stored, managed, and analyzed using Stata version 13. Results The overall percentage of women who initiated early breastfeeding was 59.22%. Rwanda recorded the highest percentage of early initiation of breastfeeding (86.34%), while Gambia recorded the lowest (39.44%). The adjusted model revealed a significant association between health facility delivery and EIB (aOR = 1.80, CI = 1.73-1.87). Compared with urban women, rural women had higher likelihood of initiating early breastfeeding (aOR = 1.22, CI = 1.16-1.27). Women with a primary education (aOR = 1.26, CI = 1.20-1.32), secondary education (aOR = 1.12, CI = 1.06-1.17), and higher (aOR = 1.13, CI = 1.02-1.25), all had higher odds of initiating early breastfeeding. Women with the richest wealth status had the highest odds of initiating early breastfeeding as compared to the poorest women (aOR = 1.33, CI = 1.23-1.43). Conclusion Based on our findings, we strongly advocate for the integration of EIB policies and initiatives with healthcare delivery advocacy. Integration of these efforts can result in drastic reduction in infant and child mortality. Essentially, Gambia and other countries with a lower proclivity for EIB must reconsider their current breastfeeding interventions and conduct the necessary reviews and modifications that can lead to an increase in EIB.
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Affiliation(s)
- Edward K. Ameyaw
- Institute of Policy Studies and School of Graduate StudiesLingnan UniversityTuen MunHong Kong
- L & E Research Consult LtdUpper West RegionGhana
| | - Kenneth S. Adde
- Department of Population and HealthUniversity of Cape CoastCape CoastGhana
| | | | - Kwamena S. Dickson
- Department of Population and HealthUniversity of Cape CoastCape CoastGhana
| | - Olanrewaju Oladimeji
- Department of Public HealthWalter Sisulu UniversityMthathaEastern CapeSouth Africa
| | - Sanni Yaya
- School of International Development and Global StudiesUniversity of OttawaOttawaOntarioCanada
- The George Institute for Global HealthImperial College LondonLondonUK
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Dickson KS, Boateng ENK, Acquah E, Ayebeng C, Addo IY. Screening for cervical cancer among women in five countries in sub-saharan Africa: analysis of the role played by distance to health facility and socio-demographic factors. BMC Health Serv Res 2023; 23:61. [PMID: 36670402 PMCID: PMC9862532 DOI: 10.1186/s12913-023-09055-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 01/10/2023] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Cervical cancer significantly affects women in Sub-Saharan Africa (SSA). However, limited studies have concentrated on cervical screening behaviour among women in SSA. This study aimed to assess the interplay of distance to health facilities and socio-demographic factors with cervical screening behaviour among women in five SSA countries. METHODS The study was based on pooled data of 40,555 women included in Demographic and Health Surveys (DHS) conducted between 2013 to 2021. Proportions and logistic regression models were used in assessing the interplay of distance to health facilities and socio-demographic factors with cervical screening behaviour. RESULTS Approximately, 7.9% of women that saw the distance to a health facility as a big problem, tested for cervical cancer compared to 13.5% who indicated that distance to a health facility is not a big problem. More women in urban areas, with a higher level of education, of richest wealth index, aged 40-44 years and using contraceptives who also indicated that distance to a health facility was a big problem tested for cervical cancer compared to those in rural areas with no education, of poorest wealth index, aged 15-19 years and not using contraceptives. Education, age, contraceptive use, frequent exposure to mass media and Sexual Transmitted Infections (STI) had a significant relationship with testing for cervical cancer. CONCLUSION The prevalence of cervical cancer screening was low in the five SSA countries largely due to distance barriers and was also significantly influenced by education, age, contraceptive use, frequent exposure to mass media, and STI status. To improve the screening for cervical cancer and its associated benefits in the five SSA countries, there is a need for policymakers, clinicians and public health workers to channel more commitment and efforts to addressing the barriers identified in this study.
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Affiliation(s)
- Kwamena S. Dickson
- grid.413081.f0000 0001 2322 8567Department of Population and Health, University of Cape Coast, Cape Coast, Ghana
| | - Ebenezer N. K. Boateng
- grid.413081.f0000 0001 2322 8567Department of Geography and Regional Planning, University of Cape Coast, Cape Coast, Ghana
| | - Evelyn Acquah
- grid.449729.50000 0004 7707 5975Centre for Health Policy and Implementation Research, Institute of Health Research, University of Health and Allied Sciences, Ho, Ghana
| | - Castro Ayebeng
- grid.413081.f0000 0001 2322 8567Department of Population and Health, University of Cape Coast, Cape Coast, Ghana
| | - Isaac Y. Addo
- grid.1005.40000 0004 4902 0432Centre for Social Research in Health, The University of New South Wales, Sydney, Australia
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Abstract
Translational activation in oocytes and embryos is often regulated via increases in poly(A) length. Cleavage and polyadenylation specificity factor (CPSF), cytoplasmic polyadenylation element binding protein (CPEB), and poly(A) polymerase (PAP) have each been implicated in cytoplasmic polyadenylation in Xenopus laevis oocytes. Cytoplasmic polyadenylation activity first appears in vertebrate oocytes during meiotic maturation. Data presented here shows that complexes containing both CPSF and CPEB are present in extracts of X. laevis oocytes prepared before or after meiotic maturation. Assessment of a variety of RNA sequences as polyadenylation substrates indicates that the sequence specificity of polyadenylation in egg extracts is comparable to that observed with highly purified mammalian CPSF and recombinant PAP. The two in vitro systems exhibit a sequence specificity that is similar, but not identical, to that observed in vivo, as assessed by injection of the same RNAs into the oocyte. These findings imply that CPSFs intrinsic RNA sequence preferences are sufficient to account for the specificity of cytoplasmic polyadenylation of some mRNAs. We discuss the hypothesis that CPSF is required for all polyadenylation reactions, but that the polyadenylation of some mRNAs may require additional factors such as CPEB. To test the consequences of PAP binding to mRNAs in vivo, PAP was tethered to a reporter mRNA in resting oocytes using MS2 coat protein. Tethered PAP catalyzed polyadenylation and stimulated translation approximately 40-fold; stimulation was exclusively cis-acting, but was independent of a CPE and AAUAAA. Both polyadenylation and translational stimulation required PAPs catalytic core, but did not require the putative CPSF interaction domain of PAP. These results demonstrate that premature recruitment of PAP can cause precocious polyadenylation and translational stimulation in the resting oocyte, and can be interpreted to suggest that the role of other factors is to deliver PAP to the mRNA.
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Affiliation(s)
- K S Dickson
- Department of Biochemistry, College of Agriculture and Life Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA
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Gray NK, Coller JM, Dickson KS, Wickens M. Multiple portions of poly(A)-binding protein stimulate translation in vivo. EMBO J 2000; 19:4723-33. [PMID: 10970864 PMCID: PMC302064 DOI: 10.1093/emboj/19.17.4723] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2000] [Revised: 07/07/2000] [Accepted: 07/12/2000] [Indexed: 11/13/2022] Open
Abstract
Translational stimulation of mRNAs during early development is often accompanied by increases in poly(A) tail length. Poly(A)-binding protein (PAB) is an evolutionarily conserved protein that binds to the poly(A) tails of eukaryotic mRNAs. We examined PAB's role in living cells, using both Xenopus laevis oocytes and Saccharomyces cerevisiae, by tethering it to the 3'-untranslated region of reporter mRNAs. Tethered PAB stimulates translation in vivo. Neither a poly(A) tail nor PAB's poly(A)-binding activity is required. Multiple domains of PAB act redundantly in oocytes to stimulate translation: the interaction of RNA recognition motifs (RRMs) 1 and 2 with eukaryotic initiation factor-4G correlates with translational stimulation. Interaction with Paip-1 is insufficient for stimulation. RRMs 3 and 4 also stimulate, but bind neither factor. The regions of tethered PAB required in yeast to stimulate translation and stabilize mRNAs differ, implying that the two functions are distinct. Our results establish that oocytes contain the machinery necessary to support PAB-mediated translation and suggest that PAB may be an important participant in translational regulation during early development.
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Affiliation(s)
- N K Gray
- Department of Biochemistry, 433 Babcock Drive, University of Wisconsin-Madison, Madison, WI 53706, USA
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Abstract
The repair of phosphodiester bonds in nicked DNA is catalyzed by DNA ligases. Ligation is coupled to cleavage of a phosphoanhydride bond in a nucleotide cofactor resulting in a thermodynamically favorable process. A free energy value for phosphodiester bond formation was calculated using the reversibility of the T4 DNA ligase reaction. The relative number of DNA nicks to phosphodiester bonds in a circular plasmid DNA, formed during this reaction at fixed concentrations of ATP to AMP and PP(i), was quantified. At 25 degrees C, pH 7, the equilibrium constant (K(eq)) for the ligation reaction is 3.89 x 10(4) m. This value corresponds to a standard free energy (DeltaG degrees ') of -6.3 kcal mol(-1). By subtracting the known energy contribution due to hydrolysis of ATP to AMP and PP(i), DeltaG degrees ' for the hydrolysis of a DNA phosphodiester bond is -5.3 kcal mol(-1).
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Affiliation(s)
- K S Dickson
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
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Barkoff AF, Dickson KS, Gray NK, Wickens M. Translational control of cyclin B1 mRNA during meiotic maturation: coordinated repression and cytoplasmic polyadenylation. Dev Biol 2000; 220:97-109. [PMID: 10720434 DOI: 10.1006/dbio.2000.9613] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Translational control is prominent during meiotic maturation and early development. In this report, we investigate a mode of translational repression in Xenopus laevis oocytes, focusing on the mRNA encoding cyclin B1. Translation of cyclin B1 mRNA is relatively inactive in the oocyte and increases dramatically during meiotic maturation. We show, by injection of synthetic mRNAs, that the cis-acting sequences responsible for repression of cyclin B1 mRNA reside within its 3'UTR. Repression can be saturated by increasing the concentration of reporter mRNA injected, suggesting that the cyclin B1 3'UTR sequences provide a binding site for a trans-acting repressor. The sequences that direct repression overlap and include cytoplasmic polyadenylation elements (CPEs), sequences known to promote cytoplasmic polyadenylation. However, the presence of a CPE per se appears insufficient to cause repression, as other mRNAs that contain CPEs are not translationally repressed. We demonstrate that relief of repression and cytoplasmic polyadenylation are intimately linked. Repressing elements do not override the stimulatory effect of a long poly(A) tail, and polyadenylation of cyclin B1 mRNA is required for its translational recruitment. Our results suggest that translational recruitment of endogenous cyclin B1 mRNA is a collaborative effect of derepression and poly(A) addition. We discuss several molecular mechanisms that might underlie this collaboration.
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Affiliation(s)
- A F Barkoff
- Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, Wisconsin 53706, USA
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Dickson KS, Bilger A, Ballantyne S, Wickens MP. The cleavage and polyadenylation specificity factor in Xenopus laevis oocytes is a cytoplasmic factor involved in regulated polyadenylation. Mol Cell Biol 1999; 19:5707-17. [PMID: 10409759 PMCID: PMC84422 DOI: 10.1128/mcb.19.8.5707] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During early development, specific mRNAs receive poly(A) in the cytoplasm. This cytoplasmic polyadenylation reaction correlates with, and in some cases causes, translational stimulation. Previously, it was suggested that a factor similar to the multisubunit nuclear cleavage and polyadenylation specificity factor (CPSF) played a role in cytoplasmic polyadenylation. A cDNA encoding a cytoplasmic form of the 100-kDa subunit of Xenopus laevis CPSF has now been isolated. The protein product is 91% identical at the amino acid sequence level to nuclear CPSF isolated from Bos taurus thymus. This report provides three lines of evidence that implicate the X. laevis homologue of the 100-kDa subunit of CPSF in the cytoplasmic polyadenylation reaction. First, the protein is predominantly localized to the cytoplasm of X. laevis oocytes. Second, the 100-kDa subunit of X. laevis CPSF forms a specific complex with RNAs that contain both a cytoplasmic polyadenylation element (CPE) and the polyadenylation element AAUAAA. Third, immunodepletion of the 100-kDa subunit of X. laevis CPSF reduces CPE-specific polyadenylation in vitro. Further support for a cytoplasmic form of CPSF comes from evidence that a putative homologue of the 30-kDa subunit of nuclear CPSF is also localized to the cytoplasm of X. laevis oocytes. Overexpression of influenza virus NS1 protein, which inhibits nuclear polyadenylation through an interaction with the 30-kDa subunit of nuclear CPSF, prevents cytoplasmic polyadenylation, suggesting that the cytoplasmic X. laevis form of the 30-kDa subunit of CPSF is involved in this reaction. Together, these results indicate that a distinct, cytoplasmic form of CPSF is an integral component of the cytoplasmic polyadenylation machinery.
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Affiliation(s)
- K S Dickson
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA
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