The specific expression patterns of lactase, sucrase and calbindin-D9k in weaning rats are regulated at the transcriptional level.
During weaning, rat lactase-phlorizin hydrolase (LPH) expression decreased to the low levels found in adults, while sucrase-isomaltase (SI) sharply increased. Calbindin-D9k (CaBP) is specific to the intestine and expression peaked within a few days of weaning. The present study investigates whether these molecules are regulated at transcriptional or post-transcriptional levels and examines the effects of diet on regulation. At normal weaning on day 21, litters were separated from their dams and one group was fed with a standard laboratory diet (weaned (W) group). The other group received a diet containing lactose as the sole source of carbohydrate (lactose-fed (L) group). Mucosal cells were obtained from the proximal part of the rat small intestine and then the activity and concentration of LPH, SI and CaBP proteins and mRNAs were determined. Three parameters revealed the same changing patterns in LPH, SI and CaBP during development and there was significant (p<0.001) correlation between three parameters: LPH, r=0.97 for activity vs. protein, r=0.99 for activity vs. mRNA, r=0.96 for protein vs. mRNA, SI, r=0.99 for activity vs. protein, r=0.98 for activity vs. mRNA, r=0.96 for protein vs. mRNA, CaBP, r=0.94 for activity vs. protein, r=0.97 for activity vs. mRNA, r=0.95 for protein vs. mRNA. Expression of the three proteins did not differ between the L and W groups. Accordingly, it has been suggested that the expression of LPH, SI and CaBP during development is defined at the transcriptional level and dietary changes do not exert a primary effect on it.
Fukushima
Akiko
A
Department of Molecular Nutrition, Kagawa Nutrition University, 3-9-21 Chiyoda, Sakado, Saitama 350-0288, Japan.
Goda
Toshinao
T
Motohashi
Yasuko
Y
Sakuma
Keiko
K
D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D064026:Calbindins; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D007421:Intestine, Small / Q000201:enzymology; D010694:Lactase-Phlorizin Hydrolase / Q000235:genetics / Q000378:metabolism*; D007785:Lactose / Q000008:administration & dosage* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D064030:S100 Calcium Binding Protein G / Q000235:genetics / Q000378:metabolism*; D013394:Sucrase-Isomaltase Complex / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014886:Weaning
D064026:Calbindins; D012333:RNA, Messenger; D064030:S100 Calcium Binding Protein G; C576508:S100g protein, rat; D013394:Sucrase-Isomaltase Complex; D010694:Lactase-Phlorizin Hydrolase; D007785:Lactose