title: The Drosophila melanogaster Muc68E Mucin Gene Influences Adult Size, Starvation Tolerance, and Cold Recovery.
abstract: Mucins have been implicated in many different biological processes, such as protection from mechanical damage, microorganisms, and toxic molecules, as well as providing a luminal scaffold during development. Nevertheless, it is conceivable that mucins have the potential to modulate food absorption as well, and thus contribute to the definition of several important phenotypic traits. Here we show that the Drosophila melanogaster Muc68E gene is 40- to 60-million-yr old, and is present in Drosophila species of the subgenus Sophophora only. The central repeat region of this gene is fast evolving, and shows evidence for repeated expansions/contractions. This and/or frequent gene conversion events lead to the homogenization of its repeats. The amino acid pattern P[ED][ED][ST][ST][ST] is found in the repeat region of Muc68E proteins from all Drosophila species studied, and can occur multiple times within a single conserved repeat block, and thus may have functional significance. Muc68E is a nonessential gene under laboratory conditions, but Muc68E mutant flies are smaller and lighter than controls at birth. However, at 4 d of age, Muc68E mutants are heavier, recover faster from chill-coma, and are more resistant to starvation than control flies, although they have the same percentage of lipids as controls. Mutant flies have enlarged abdominal size 1 d after chill-coma recovery, which is associated with higher lipid content. These results suggest that Muc68E has a role in metabolism modulation, food absorption, and/or feeding patterns in larvae and adults, and under normal and stress conditions. Such biological function is novel for mucin genes.
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Portugal Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Portugal.
authors.forename: Micael
authors.initials: M
authors.lastname: Reis
authors.affiliation: Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, NG7 2RD United Kingdom.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Silva
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Portugal Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Portugal.
authors.forename: Cristina P
authors.initials: CP
authors.lastname: Vieira
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Portugal Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Portugal jbvieira@ibmc.up.pt.
authors.forename: Jorge
authors.initials: J
authors.lastname: Vieira
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D049628:Body Size; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D004734:Energy Metabolism / Q000235:genetics; D005260:Female; D065569:Gastrointestinal Absorption / Q000235:genetics; D015870:Gene Expression; D008136:Longevity; D008297:Male; D009077:Mucins / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D013217:Starvation / Q000235:genetics*
chemical_list: D029721:Drosophila Proteins; D009077:Mucins
keywords: Drosophila melanogaster; Muc68E; cold resistance; mucin; starvation tolerance