title: A human-specific gene in microglia.
abstract: Recent studies have shown multiple differences between humans and apes in sialic acid (Sia) biology, including Siglecs (Sia-recognizing-Ig-superfamily lectins). Comparisons with the chimpanzee genome indicate that human SIGLEC11 emerged through human-specific gene conversion by an adjacent pseudogene. Conversion involved 5 cent untranslated sequences and the Sia-recognition domain. This human protein shows reduced binding relative to the ancestral form but recognizes oligosialic acids, which are enriched in the brain. SIGLEC11 is expressed in human but not in chimpanzee brain microglia. Further studies will determine if this event was related to the evolution of Homo.
authors.affiliation: Glycobiology Research and Training Center, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Hayakawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Angata
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Lewis
authors.forename: Tarjei S
authors.initials: TS
authors.lastname: Mikkelsen
authors.forename: Nissi M
authors.initials: NM
authors.lastname: Varki
authors.forename: Ajit
authors.initials: A
authors.lastname: Varki
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001921:Brain / Q000378:metabolism*; D005091:Exons; D005785:Gene Conversion; D006801:Humans; D037102:Lectins / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D017628:Microglia / Q000378:metabolism*; D002679:Pan troglodytes / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D011148:Pongo pygmaeus / Q000235:genetics / Q000378:metabolism; D011544:Pseudogenes; D012045:Regulatory Sequences, Nucleic Acid; D012794:Sialic Acids / Q000378:metabolism
chemical_list: D037102:Lectins; D008565:Membrane Proteins; C464442:SIGLEC11 protein, human; D012794:Sialic Acids