Developmental and tissue-specific regulation of ovine insulin-like growth factor II (IGF-II) mRNA expression.
Insulin-like growth factor II (IGF-II) is believed to be involved in the development of the fetus. Northern and dot-blot analysis of RNA isolated from different sheep tissues at various stages of development were undertaken, revealing that the ovine IGF-II gene is expressed as a multitranscript family (6.0, 5.1, 5.0, 4.7, 3.8, 2.9, 2.3, 1.9, 1.6, 1.3 kb). Evidence that the ovine IGF-II gene may be regulated in a developmental, tissue-specific, co-ordinate or independent manner is presented. The developmental profile of IGF-II gene expression correlates with plasma levels (Mesiano et al. (1989) Endocrinology 124, 1485-1491), and suggests that the rapid fall in plasma concentration at term can be attributed to regulation at the transcriptional level. With the exception of the kidney, IGF-II expression was down-regulated at birth in all tissues examined. As in man but not rat, an adult liver-specific transcript was detected and attributed to different 5' untranslated regions in the fetal and adult IGF-II mRNAs. The finding of IGF-II transcripts in all tissues examined supports evidence from other species of autocrine/paracrine roles for IGF-II in the development of the fetus.
School of Veterinary Science, University of Melbourne, Parkville, Victoria, Australia.
J V
JV
O'Mahoney
M R
MR
Brandon
T E
TE
Adams
D000818:Animals; D001483:Base Sequence; D005314:Embryonic and Fetal Development; D005786:Gene Expression Regulation / Q000187:drug effects; D007335:Insulin-Like Growth Factor II / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D009132:Muscles / Q000196:embryology / Q000378:metabolism; D009928:Organ Specificity; D010920:Placenta / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D012756:Sheep / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D013045:Species Specificity; D014158:Transcription, Genetic; D014781:Viscera / Q000196:embryology / Q000378:metabolism
D012333:RNA, Messenger; D007335:Insulin-Like Growth Factor II