Targeted pituitary tumorigenesis using the human thyrotropin beta-subunit chain promoter in transgenic mice.
We have generated transgenic mice that express the simian virus 40 (SV40) large T antigen under the control of a 1109 bp 5'-flanking sequence of the human thyrotropin beta-subunit (TSH beta) gene. The hybrid gene, termed TTP-1, was microinjected into fertilized mouse eggs and 11 transgenic mice were obtained. One of the transgenic mice, a female, a phenotypical dwarf, developed a pituitary tumor and wasted away from 7 to 9 weeks after birth. To establish the transgenic mouse line, her ovaries were transferred to a normal female, whose ovaries were removed beforehand. To examine the tissue specificity of transgene expression, mRNA of SV40 large T antigen was monitored in various tissues from the transgenic mice by the reverse transcriptase-polymerase chain reaction analysis, and was detected only in the pituitary. Histological and immunohistochemical analyses showed that the pituitary tumors of the transgenic mice were composed of poorly differentiated pituitary cells expressing SV40 large T antigen. These results indicated that the 1109 bp sequence of the human TSH beta 5'-flanking region is essential for pituitary-specific expression of SV40 large T antigen in transgenic mice, which exhibited a dwarf phenotype and developed pituitary tumors. The tumors were composed of undifferentiated cells and did not produce thyrotropin. These transgenic mice should provide a valuable animal model for studying the pathogenesis of anterior pituitary tumors.
Department of Laboratory Animal Science, School of Medicine, Hokkaido University, Sapporo, Japan.
K
K
Maki
I
I
Miyoshi
Y
Y
Kon
T
T
Yamashita
N
N
Sasaki
S
S
Aoyama
E
E
Takahashi
S
S
Namioka
Y
Y
Hayashizaki
N
N
Kasai
D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000032:analysis / Q000235:genetics; D001483:Base Sequence; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000473:pathology; D017931:DNA Primers / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D010903:Pituitary Gland, Anterior / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D010911:Pituitary Neoplasms / Q000209:etiology* / Q000235:genetics* / Q000276:immunology; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D013972:Thyrotropin / Q000032:analysis / Q000235:genetics*
D000952:Antigens, Polyomavirus Transforming; D017931:DNA Primers; D012333:RNA, Messenger; D013972:Thyrotropin