The endosperm of cereal grains is one of the most valuable products of modern agriculture. Cereal endosperm development comprises different phases characterized by mitotic cell proliferation, endoreduplication, the accumulation of storage compounds, and programmed cell death. Although manipulation of these processes could maximize grain yield, how they are regulated and integrated is poorly understood. We show that the Retinoblastoma-related (RBR) pathway controls key aspects of endosperm development in maize. Down-regulation of RBR1 by RNAi resulted in up-regulation of RBR3-type genes, as well as the MINICHROMOSOME MAINTE-NANCE 2-7 gene family and PROLIFERATING CELL NUCLEAR ANTI-GEN, which encode essential DNA replication factors. Both the mitotic and endoreduplication cell cycles were stimulated. Developing transgenic endosperm contained 42-58% more cells and ∼70% more DNA than wild type, whereas there was a reduction in cell and nuclear sizes. In addition, cell death was enhanced. The DNA content of mature endosperm increased 43% upon RBR1 downregulation, whereas storage protein content and kernel weight were essentially not affected. Down-regulation of both RBR1 and CYCLIN DEPENDENT KINASE A (CDKA);1 indicated that CDKA;1 is epistatic to RBR1 and controls endoreduplication through an RBR1-dependent pathway. However, the repressive activity of RBR1 on downstream targets was independent from CDKA;1, suggesting diversification of RBR1 activities. Furthermore, RBR1 negatively regulated CDK activity, suggesting the presence of a feedback loop. These results indicate that the RBR1 pathway plays a major role in regulation of different processes during maize endosperm development and suggest the presence of tissue/organlevel regulation of endosperm/seed homeostasis. seed development | endocycle T he seed endosperm is a triploid tissue resulting from the fusion of one haploid sperm nucleus with the diploid central cell nucleus within the female gametophyte. Development of the endosperm in flowering plants is characterized by acytokinetic mitoses of the primary endosperm nucleus, resulting in a syncytium, cellularization of syncytial nuclear domains, and cell proliferation through mitotic activity that is coupled to cell division (1, 2). Additionally, in the Poaceae (grass) family, the endosperm undergoes a rapid growth phase that coincides with accumulation of storage compounds, such as starch and storage proteins, during a specialized type of cell cycle known as endoreduplication. Endoreduplication is characterized by one or more rounds of DNA synthesis in the absence of mitosis, resulting in polyploid cells (3-5). Endoreduplication is highly correlated with cell size in many plant and animal tissues, but its role in endosperm development has not been established. Upon completion of endoreduplication and storage metabolite synthesis, cereal endosperm cells undergo programmed cell death (PCD), resulting in extensive DNA degradation (5, 6). In maize (Zea mays L.), endosperm cells transition from a mitotic to an endore...

No abstract

Purpose-To explore contraceptive counseling and utilization among breast cancer survivors. Methods-This is a cross-sectional study. We enrolled reproductive-aged women with a history of breast cancer for a cross-sectional study. Participants were recruited via the Athena Breast Health Network and via the Young Survival Coalition's social media postings. Descriptive statistics were calculated to understand utilization of and feelings about contraceptive methods before, during, and after breast cancer treatment. Results-Data presented here are from an online survey of 150 breast cancer survivors who completed the survey. Seventy-one percent (n=105) of respondents reported being sexually active and not pregnant during their primary cancer treatment (surgery, chemotherapy, and/or radiation). Of these, 90% (n=94) reported using any form of contraceptive, and the most common method was condoms (n=55, 52%). Respondents reported that safety concerns had the biggest influence on their contraception method choice. Sixty-one percent (n=92) reported receiving contraceptive Terms of use and reuse: academic research for non-commercial purposes, see here for full terms. http://www.springer.com/gb/openaccess/authors-rights/aam-terms-v1

Objective Elevated anxiety and breast cancer worry can impede mammographic screening and early breast cancer detection. Genetic advances and risk models make personalized breast cancer risk assessment and communication feasible, but it is unknown whether such communication of risk affects anxiety and disease‐specific worry. We studied the effect of a personalized breast cancer screening intervention on risk perception, anxiety, and breast cancer worry. Methods Women with a normal mammogram but elevated risk for breast cancer (N = 122) enrolled in the Athena Breast Health risk communication program were surveyed before and after receiving a letter conveying their breast cancer risk and a breast health genetic counselor consultation. We compared breast cancer risk estimation, anxiety, and breast cancer worry before and after risk communication and evaluated the relationship of anxiety and breast cancer worry to risk estimation accuracy. Results Women substantially overestimated their lifetime breast cancer risk, and risk communication somewhat mitigated this overestimation (49% pre‐intervention, 42% post‐intervention, 13% Gail model risk estimate, P < .001). Both general anxiety and breast cancer worry declined significantly after risk communication in women with high baseline anxiety. Baseline anxiety and breast cancer worry were essentially unrelated to risk estimation accuracy, but risk communication increased alignment of worry with accuracy of risk assessment. Conclusions Personalized communication about breast cancer risk was associated with modestly improved risk estimation accuracy in women with relatively low anxiety and less anxiety and breast cancer worry in women with higher anxiety. We detected no negative consequences of informing women about elevated breast cancer risk.

No abstract