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The Drosophila sticks-and-stones (sns) locus has been identified based on its mutant phenotype, absence of body wall muscles and presence of unfused myoblasts. The genetic location of the mutation that brings on the apparent defect in myoblast fusion has been found by recombination and deficiency mapping. Drosophila SNS has been found to be a member of the immunoglobulin superfamily required for myoblast fusion.

Myocyte-specific enhancer-binding factor 2 (MEF2) is a myogenic regulatory factor in vertebrates and Drosophila. Whereas the role of MEF2 in regulating vertebrate myogenesis and muscle genes has been extensively studied, little is known of the role of MEF2 in regulating Drosophila myogenesis. We have shown in a recent analysis of the regulation of the Drosophila Tropomyosin I (TmI) gene in transgenic flies that MEF2 is a positive regulator of TmI expression in the somatic body-wall muscles of embryos, larvae, and adults. To understand further the role of MEF2 in myogenesis and test the role of MEF2 in regulating TmI expression, we have used the yeast GAL4/UAS system to generate embryos in which MEF2 is ectopically expressed in tissues where it is not normally expressed or embryos in which MEF2 is overexpressed in the mesoderm and muscles. We observe that ectopic expression of MEF2 in the epidermis and the ventral midline cells in embryos activates the expression of TmI and other muscle genes in these tissues and that this activation is stage-dependent suggesting a requirement for additional factors. Furthermore, ectopic expression of MEF2 in the epidermis results in a decrease in the expression of signaling molecules in the epidermis and a failure of the embryo to properly form body-wall muscles. These results indicate that MEF2 can function out of context in the epidermis to induce the expression of muscle genes and interfere with a requirement for the epidermis in muscle development. We also find that the level of MEF2 in the mesoderm and/or muscles in embryos is critical to body-wall muscle formation; however, no effect is observed on the development of the visceral muscle or dorsal vessel.

Background. Cancer rehabilitation is a developing area, with an increasing number of survivors of cancer in the United States. The increase in survivorship occurs alongside impairments arising directly from cancer or from treatment-related side effects. Objective. This study described clinical characteristics of patients with cancer referred for outpatient physical therapy and explored patterns in frequency of impairments between type of cancer and mode of cancer treatment. Design. This was a retrospective chart review of patients with cancer referred to a tertiary care physical therapy clinic over a 2-year period. Methods. Characteristics such as age, sex, cancer type, mode of treatment, and neuromusculoskeletal impairments were identified. Impairment frequencies were computed based on cancer type and mode of treatment. Results. Data from 418 patients (mean age=57.9 years, SD=14.3; 41.1% female) were examined. Genitourinary cancer (n=l69) and breast cancer (n=90) were the most prevalent types of cancer reported in this sample. Impairments in strength (83-6%) and soft tissue (71.3%) were the most common examination findings. Lymphedema was most common in patients with breast cancer, and incontinence was most common in patients with genitourinary cancer. Limitations. The types of cancer identified in this study may be reflective of this tertiary center and may not generalize to other facilities. Impairment identification during the initial physical therapist evaluation was not performed systematically. Conclusion. These data reinforce that physical therapists should screen for lymphedema in patients with breast cancer and incontinence in urogenital cancers. Strength and soft tissue integrity should be evaluated in most patients with cancer. Assessing pain and fatigue levels is recommended for patients who have had radiation therapy. [ABSTRACT FROM AUTHOR]