Research Briefs

A Sperm Finds Its Egg Courtesy of Richard Mooi For sea urchins, sex is an out-of-body experience. And in external fertilization, species-specific gamete receptors serve as one way to prevent cross-fertilization. The discovery of an egg protein responsible for this specificity ended a 25-year quest for Charles Glabe, molecular biologist at University of California, Irvine. Glabe and postdoc Noriko Kamei identified the glycoprotein on sea urchin eggs, called egg bindin receptor 1 (EBR1), which is involved in sperm recognition for two sea urchin species.1 A rapidly evolving species-specific domain makes up one-third to one-half of the 350 kDa protein. The technique that facilitated EBR1's discovery, representation difference analysis, is "a quick way to identify rapidly evolving genes in closely related species," says Glabe. Because of their specificity, these proteins prevent hybridization and provide "a reasonable dividing line between one species and another." Victor Vacquier, Glabe's former doctoral adviser now at the Scripps Institute of Oceanography, described bindin (the sperm's egg attachment protein) in 1977.2 He says this new discovery raises questions about EBR1's variance in populations. "Is it the forerunner of the speciation event, or does divergence take place after speciation has occurred? This sets the stage for lots of interesting molecular studies." --Maria W. Anderson References 1. N. Kamei, C. Glabe, "The species-specific egg receptor for sea urchin sperm adhesion is EBR1, a novel ADAMTS protein," Genes Dev, 17:2502-7, Oct. 15, 2003. 2. V. Vacquier, G. Moy, "Isolation of bindin: the protein responsible for adhesion of sperm to sea urchin eggs," Proc Natl Acad Sci, 74:2456-60, 1977. Gobbler Genome Tapped Courtesy of Keith Weller, ARS image Gallery Researchers mapped 113 genes among the 22 chromosomes of Meleagris gallopavo, the domestic turkey, providing a framework for genome sequencing.1 "It's too early to tell what will be economically important and what will not," says David Harry, president of Genetic Foundations of Napa, Calif. Tom Savage, animal science professor at Oregon State University in Corvallis, says he's excited. "With an understanding of the turkey's genome, the breeder can improve the quality of the bird." But, the chicken has long outstripped the turkey in genome sequencing priority. "The turkey just doesn't have the level of background biological research as does the chicken," says Harry, formerly a molecular geneticist with Nicholas Turkey Breeding Farms in Sonoma, Calif. Models for cancer viruses, steroid regulation, chromatin structure, and lymphocyte distinctions were all worked out in chickens. Inequities continue at the dinner table, too; US citizens consume an average of 80 pounds of chicken each year but only 18 pounds of turkey, according to the Poultry Science department at the University of Georgia in Athens. The mapped genes include "novel sequences" that may extend the short list of known turkey variants, such as head-wobbling "vibrators" and "naked" turkeys, both discovered in 1961. Savage uses genetics to dispel a turkey myth: "Turkeys will not drown if they look up while it is raining. The turkey seen in the field with its head retracted may be suffering from tetanic torticollar spasms," he says. --Ricki Lewis 1. D. Harry et al., "A first-generation map of the turkey genome," Genome, 46:914-924, October 2003. Interdisciplinary Research These papers were selected from multiple disciplines from the Faculty of 1000, a Web-based literature awareness tool (www.facultyof1000.com). A.A. Aravin et al., "The small RNA profile during Drosophila melanogaster development," Dev Cell, 5:337-50, Aug 5, 2003. "Cloning of small RNAs in Drosophila has recovered 62 nonredundant microRNAs and 178 repeat-associated small interfering RNAs (rasiRNAs), suggesting an extensive role for RNA-mediated posttranscriptional and transcriptional gene silencing in this organism .... These rasiRNAs potentially regulate transposon mobility and assembly of heterochromatin at transposon-rich regions such as telomeres and centromeres." --Marjori Matzke, Australian Academy of Sciences E. Mossessova et al., "SNARE selectivity of the COPII coat," Cell, 114: 483-95, Aug. 22, 2003. "The authors suggest that the vesicle coat protein complex COPII selects certain SNARE complex combinations to program the vesicle for the fusion with the right target membrane. They found that three SNARE/SNARE complexes are recognized by three different binding sites in Sec24 and are subsequently recruited into COPII vesicles." --Anne Spang, Friedrich Miescher Laboratory, Germany E.A. Miller et al., "Multiple cargo binding sites on the COPII subunit Sec24p ensure capture of diverse membrane proteins into transport vesicles," Cell, 114:497-509, Aug. 22, 2003. "Using a yeast genetic approach, the authors identify two distinct binding sites involved in cargo signal recognition by the Sec24 component of the COPII protein coat complex, which functions in vesicle budding and cargo sorting from the endoplasmic reticulum .... The conclusions of this study corroborate the observations of an independent crystallographic/biophysical analysis published in the same issue [above]." --David Lambright, University of Massachusetts Medical School function sendData() { document.frm.pathName.value = location.pathname; result = false if (document.frm.score[0].checked) result = true; if (document.frm.score[1].checked) result = true; if (document.frm.score[2].checked) result = true; if (document.frm.score[3].checked) result = true; if (document.frm.score[4].checked) result = true; if (!result) alert("Please select") return result; } .myradio{background-color : #94bee5} Please indicate on a 1 - 5 scale how strongly you would recommend this article to your colleagues? Not recommended 1 2 3 4 5 Highly recommended Please register your vote

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