Chancellery Research - Research Publications

Permanent URI for this collection

Search Results

Now showing 1 - 10 of 22
  • Item
    Thumbnail Image
    A mosaic genetic screen for novel mutations affecting Drosophila neuroblast divisions
    Slack, C ; Somers, WG ; Sousa-Nunes, R ; Chia, W ; Overton, PM (BIOMED CENTRAL LTD, 2006-06-02)
    BACKGROUND: The asymmetric segregation of determinants during cell division is a fundamental mechanism for generating cell fate diversity during development. In Drosophila, neural precursors (neuroblasts) divide in a stem cell-like manner generating a larger apical neuroblast and a smaller basal ganglion mother cell. The cell fate determinant Prospero and its adapter protein Miranda are asymmetrically localized to the basal cortex of the dividing neuroblast and segregated into the GMC upon cytokinesis. Previous screens to identify components of the asymmetric division machinery have concentrated on embryonic phenotypes. However, such screens are reaching saturation and are limited in that the maternal contribution of many genes can mask the effects of zygotic loss of function, and other approaches will be necessary to identify further genes involved in neuroblast asymmetric division. RESULTS: We have performed a genetic screen in the third instar larval brain using the basal localization of Miranda as a marker for neuroblast asymmetry. In addition to the examination of pupal lethal mutations, we have employed the MARCM (Mosaic Analysis with a Repressible Cell Marker) system to generate postembryonic clones of mutations with an early lethal phase. We have screened a total of 2,300 mutagenized chromosomes and isolated alleles affecting cell fate, the localization of basal determinants or the orientation of the mitotic spindle. We have also identified a number of complementation groups exhibiting defects in cell cycle progression and cytokinesis, including both novel genes and new alleles of known components of these processes. CONCLUSION: We have identified four mutations which affect the process of neuroblast asymmetric division. One of these, mapping to the imaginal discs arrested locus, suggests a novel role for the anaphase promoting complex/cyclosome (APC/C) in the targeting of determinants to the basal cortex. The identification and analysis of the remaining mutations will further advance our understanding of the process of asymmetric cell division. We have also isolated a number of mutations affecting cell division which will complement the functional genomics approaches to this process being employed by other laboratories. Taken together, these results demonstrate the value of mosaic screens in the identification of genes involved in neuroblast division.
  • Item
    Thumbnail Image
    Health status and labour force participation: evidence from Australia
    Cai, LX ; Kalb, G (JOHN WILEY & SONS LTD, 2006-03)
    This paper examines the effect of health on labour force participation using the Household, Income and Labour Dynamics in Australia (HILDA) Survey. The potential endogeneity of health, especially self-assessed health, in the labour force participation equation is addressed by estimating the health equation and the labour force participation equation simultaneously. Taking into account the correlation between the error terms in the two equations, the estimation is conducted separately for males aged 15-49, males aged 50-64, females aged 15-49 and females aged 50-60. The results indicate that better health increases the probability of labour force participation for all four groups. However, the effect is larger for the older groups and for women. As for the feedback effect, it is found that labour force participation has a significant positive impact on older females' health, and a significant negative effect on younger males' health. For younger females and older males, the impact of labour force participation on health is not significant. The null-hypothesis of exogeneity of health to labour force participation is rejected for all groups.
  • Item
  • Item
    Thumbnail Image
    Characterization of two whey protein genes in the Australian dasyurid marsupial, the stripe-faced dunnart (Sminthopsis macroura)
    De Leo, AA ; Lefevre, C ; Topcic, D ; Pharo, E ; Cheng, JF ; Frappell, P ; Westerman, M ; Graves, JAM ; Nicholas, KR (KARGER, 2006)
    We report the first isolation and sequencing of genomic BAC clones containing the marsupial milk protein genes Whey Acidic Protein (WAP) and Early Lactation Protein (ELP). The stripe-faced dunnart WAPgene sequence contained five exons, the middle three of which code for the WAPmotifs and four disulphide core domains which characterize WAP. The dunnart ELPgene sequence contained three exons encoding a protein with a Kunitz motif common to serine protease inhibitors. Fluorescence in situ hybridization located the WAPgene to chromosome 1p in the stripe-faced dunnart, and the ELPgene to 2q. Northern blot analysis of lactating mammary tissue of the closely related fat-tailed dunnart has shown asynchronous expression of these milk protein genes. ELPwas expressed at only the earlier phase of lactation and WAPonly at the later phase of lactation, in contrast to beta-lactoglobulin (BLG) and alpha-lactalbumin (ALA) genes, which were expressed in both phases of lactation. This asynchronous expression during the lactation cycle in the fat-tailed dunnart is similar to other marsupials and it probably represents a pattern that is ancestral to Australian marsupials.
  • Item
    Thumbnail Image
    Accurate discovery of co-derivative documents via duplicate text detection
    Bernstein, Y ; Zobel, J (PERGAMON-ELSEVIER SCIENCE LTD, 2006-11)
  • Item
    Thumbnail Image
    A couples-based approach to the problem of workless families
    Cobb-Clark, D ; Ryan, C ; Breunig, R (WILEY, 2006-12)
    The objective of this paper is to evaluate a ‘couples‐based’ policy intervention designed to reduce the number of Australian families with dependent children in which no adult was in paid employment. Selected women on family benefits (who were partnered with men receiving unemployment benefits) were randomly invited to participate in an interview process designed to identify strategies for increasing economic and social participation. The overall effect of the interview process led to lower hours of work among family benefit recipients, but to greater participation in job search and in study or training for work‐related reasons. Whether women were interviewed with their partner or not had no effect on the level of economic activity of participants.
  • Item
  • Item
  • Item
  • Item
    Thumbnail Image
    Creating low skilled jobs by subsidizing market-contracted household work
    Brueck, T ; Haisken-De New, JP ; Zimmermann, KF (ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2006-05-10)