title: Cloning and expression of a type IX-like collagen in tissues of the ascidian Ciona intestinalis.
abstract: Collagens are highly preserved proteins in invertebrates and vertebrates. To identify the collagens in urochordates, the total RNA extracted from the pharynx of the ascidian Ciona intestinalis was hybridized with a heterologous probe specific for the echinoderm Paracentrotus lividus fibrillar type I-like larval collagen. Using this probe, two main bands (i.e. 6 and 2.8 kb mRNA) were observed on Northern blot hybridization. The cDNA library prepared from poly(A)+RNA extracted from pharyngeal tissue was screened and a cDNA that specifies a type IX-like collagen was identified. This molecule presents a conceptual open reading frame for a protein containing 734 amino acids. In particular, we showed a 1 alpha chain type IX-like collagen characterized by three short triple-helical domains interspersed with four non-triple-helical sequences, with structural features of fibril-associated collagens with interrupted triple-helices (FACIT) collagens. Northern blot hybridizations indicate a 2.8 kb transcript size. Sequence comparison indicated homology (47.64%, 48.95%) between the type IX-like collagen of C. intestinalis and mouse and human type IX collagen. In situ hybridization of tunic and pharynx tissues shows the presence of transcripts in connective tissue cells.
authors.affiliation: Department of Animal Biology, University of Palermo, via Archirafi 18, 90123 Palermo, Italy.
authors.forename: Aiti
authors.initials: A
authors.lastname: Vizzini
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Arizza
authors.forename: Melchiorre
authors.initials: M
authors.lastname: Cervello
authors.forename: Matteo
authors.initials: M
authors.lastname: Cammarata
authors.forename: Roberto
authors.initials: R
authors.lastname: Gambino
authors.forename: Nicolò
authors.initials: N
authors.lastname: Parrinello
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002938:Ciona intestinalis / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D024081:Collagen Type IX / Q000096:biosynthesis* / Q000235:genetics*; D015723:Gene Library; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000096:biosynthesis; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014158:Transcription, Genetic
chemical_list: D024081:Collagen Type IX; D012333:RNA, Messenger