title: Chicken oviduct-specific expression of transgene by a hybrid ovalbumin enhancer and the Tet expression system.
abstract: We generated genetically manipulated chickens and quail by infecting them with a retroviral vector expressing the human growth hormone under the control of chicken ovalbumin promoter/enhancer up to -3861 bp from the transcriptional start site. The growth hormone was expressed in an oviduct-specific manner and was found in egg white, although its level was low. The DNA sequence of the integrated form of the viral vector in the packaging cells was shown to be truncated and contained only the sequence spanning -3861 to -1569 bp. This represented only the DNase I hypersensitive site (DHS) III of the 4 DHSs and lacked the proximal promoter of the ovalbumin control region. We found several TATA-like and other promoter motifs of approximately -1800 bp and considered that these promoter motifs and DHS III may cause weak but oviduct-specific expression of the growth hormone. To prove this hypothesis and apply this system to oviduct-specific expression of the transgene, the truncated regulatory sequence was fused to an artificial transactivator-promoter system. In this system, initial weak but oviduct-specific expression of the Tet activator from the promoter element in the ovalbumin control sequence triggered a self-amplifying cycle of expression. DsRed was specifically expressed in oviduct cells of genetically manipulated chickens using this system. Furthermore, deletion of a short region possibly containing the promoter elements (-2112 to -1569 bp) completely abrogated oviduct-specific expression. Taken together, these results suggest that weak expression of this putative promoter causes oviduct-specific expression of the transgene.
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kodama
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nishimiya
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Nishijima
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Okino
authors.forename: Yujin
authors.initials: Y
authors.lastname: Inayoshi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kojima
authors.forename: Ken-Ichiro
authors.initials: K
authors.lastname: Ono
authors.forename: Makoto
authors.initials: M
authors.lastname: Motono
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Miyake
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kawabe
authors.forename: Kenji
authors.initials: K
authors.lastname: Kyogoku
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamashita
authors.forename: Masamichi
authors.initials: M
authors.lastname: Kamihira
authors.forename: Shinji
authors.initials: S
authors.lastname: Iijima
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002642:Chick Embryo; D002645:Chickens / Q000235:genetics* / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D005260:Female; D019382:Human Growth Hormone / Q000235:genetics; D006801:Humans; D010047:Ovalbumin / Q000235:genetics* / Q000378:metabolism; D010057:Oviducts / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D019076:Transgenes
chemical_list: D012097:Repressor Proteins; D015534:Trans-Activators; C034811:tetracycline resistance-encoding transposon repressor protein; D019382:Human Growth Hormone; D010047:Ovalbumin