The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 15, 1993
Filed:
May. 04, 1987
Applicant:
Inventors:
Noboru Tomioka, Mobara, JP;
Fumio Omae, Yokohama, JP;
Eriko Mine, Taito, JP;
Tomoko Ishii, Chosei, JP;
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C12P / ; C12N / ; C12N / ; C12N / ;
U.S. Cl.
CPC ...
435 691 ; 435 91 ; 4351723 ; 4352402 ; 4353201 ; 4352351 ; 536 232 ; 530350 ; 935-9 ; 935 32 ; 935 34 ; 935 42 ; 935 57 ; 935 61 ; 935 70 ;
Abstract
By screening an animal cell transformant, which has been obtained by introducing into wild-type animal cells a wild-type DHFR gene and a structural gene which codes a desired useful substance, with a medium containing methotrexate (MTX) at a concentration of 50 .mu.M or lower, both genes can be amplified effectively within an MTX resistant strain and a stable amplified transformant can also be obtained. The screening may be repeated using an increasing concentration of MTX. It is also possible to obtain stably the desired foreign gene product in a high yield by using the thus-obtained amplified transformant.