Laminin receptor expression in rat intestine and liver during development and differentiation.
OBJECTIVE
Studies have identified a 67-kilodalton high-affinity laminin receptor (LR) whose expression has also been related to development, differentiation, and neoplastic transformation. The relationship of the 67-kilodalton LR to hepatic and enterocyte development and to enterocyte differentiation was investigated.


METHODS
LR messenger RNA (mRNA) was identified using a complementary DNA isolated from a rat crypt cell library. LR and integrin (alpha 6, beta 1, and beta 4) expression by rat intestinal crypt cells was compared with that of the more differentiated villus cells using Northern blotting. Developmental differences in LR expression were studied in fetal and neonatal rats. The pattern of LR expression in fetal and adult rat intestines was examined further by in situ hybridization.


RESULTS
LR mRNA levels were highest in fetal liver and intestine and adult rat crypt cells. LR mRNA levels were 9-10 times greater in crypt than in villus cells. Integrin subunit expression differed little between crypt and villus cells. Nascent transcription studies showed that the proportion of newly transcribed LR mRNA per total RNA synthesized was similar for crypt and villus cells, suggesting posttranscriptional control of LR mRNA levels in villus cells.


CONCLUSIONS
Increased LR mRNA expression is a feature of the fetal intestine and of the undifferentiated, mitotically active crypt cells.
Rao
M
M
Department of Medicine, State University of New York at Buffalo.
Manishen
W J
WJ
Maheshwari
Y
Y
Sykes
D E
DE
Siyanova
E Y
EY
Tyner
A L
AL
Weiser
M M
MM
D000375:Aging / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000378:metabolism*; D001483:Base Sequence; D015342:DNA Probes / Q000235:genetics; D005314:Embryonic and Fetal Development; D005333:Fetus / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000166:cytology / Q000196:embryology; D008099:Liver / Q000196:embryology / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D017474:Receptors, Laminin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D015342:DNA Probes; D012333:RNA, Messenger; D017474:Receptors, Laminin