title: Kinetics of neurotensin gene expression in the developing gut.
abstract: BACKGROUND
  Expression of the gene encoding neurotensin (NT/N) is regulated in a strict temporal- and spatial-specific pattern during gut development; the mechanisms (that is, transcriptional versus posttranscriptional) responsible for this expression pattern are not known. The purpose of this study was to determine whether developmental changes in NT/N expression reflect alternations in gene transcription.
  
  
  METHODS
  Sensitive ribonuclease protection assays were performed with a rat NT/N genomic probe containing the entire sequence of both exon 1 and intron 1 hybridized with RNA from fetal (day 19) and postnatal (days 14, 28, and 60) rat jejunum and ileum; signals were quantitated densitometrically.
  
  
  RESULTS
  Mature (exon 1) and precursor (exon 1 + intron 1) NT/N RNA, initially low in the fetus, increased dramatically by postnatal day 14 and attained maximal levels by day 28. NT/N RNA levels remained stable in the ileum of the 60-day-old rat but decreased in the jejunum, consistent with the typical expression pattern in the gut.
  
  
  CONCLUSIONS
  Concomitant changes in expression of precursor and mature NT/N RNA suggest that NT/N gene regulation occurs at the level of transcription in the gut during development. Identifying the factors that regulate NT/N gene transcription is crucial to our understanding of how neurotensin functions in the gut.
authors.affiliation: Department of Surgery, University of Texas Medical Branch, Galveston 77555-0527, USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Evers
authors.forename: X F
authors.initials: XF
authors.lastname: Wang
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001345:Autoradiography / Q000379:methods; D005314:Embryonic and Fetal Development; D005091:Exons; D005260:Female; D005333:Fetus; D015870:Gene Expression; D005786:Gene Expression Regulation; D005865:Gestational Age; D007082:Ileum / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D007421:Intestine, Small / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D007438:Introns; D007583:Jejunum / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D007700:Kinetics; D024510:Muscle Development; D009130:Muscle, Smooth / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D009496:Neurotensin / Q000096:biosynthesis*; D011247:Pregnancy; D051381:Rats; D011916:Rats, Inbred F344; D012680:Sensitivity and Specificity; D014158:Transcription, Genetic
chemical_list: D009496:Neurotensin