PMID- 10516089
OWN - NLM
STAT- MEDLINE
DCOM- 19991122
LR  - 20181201
IS  - 0002-9513 (Print)
IS  - 0002-9513 (Linking)
VI  - 277
IP  - 4
DP  - 1999 Oct
TI  - Molecular mechanism of the intestinal biotin transport process.
PG  - C605-13
LID - 10.1152/ajpcell.1999.277.4.C605 [doi]
AB  - Previous studies have characterized different aspects of the cellular/membrane
      mechanism and regulation of the intestinal uptake process of the water-soluble
      vitamin biotin. Little, however, is known about the molecular mechanisms of the
      uptake process. In this study, we have identified a cDNA from rat small intestine
      that appears to be involved in biotin transport. The open reading frame of this
      cloned cDNA consisted of 1,905 bases and was identical to that identified for the
      vitamin transporter in placental tissue. Significant heterogeneity, however, was 
      found in the 5' untranslated region of this clone, with three distinct variants
      (II, III, IV) being identified in the small intestine; the placental variant
      (variant I), however, was not present in the small gut. Variant II was found to
      be the predominant form expressed in the rat small and large intestines.
      Functional identity of the cloned intestinal cDNA was confirmed by stable
      expression in COS-7 cells, which showed a four- to fivefold increase in biotin
      uptake in transfected COS-7 cells compared with controls. The induced biotin
      uptake in transfected COS-7 cells was found to be 1) Na(+) dependent, 2)
      saturable as a function of concentration with an apparent K(m) of 8. 77 microM
      and a V(max) of 779.7 pmol. mg protein(-1). 3 min(-1), and 3) inhibited by
      unlabeled biotin and pantothenic acid and their structural analogs. The
      distribution of complementary mRNA transcripts of the cloned cDNA along the
      vertical and longitudinal axes of the intestinal tract was also determined.
      Results of this study describe the molecular characteristics of the intestinal
      biotin absorption process and report the identification of a cDNA that encodes a 
      Na(+)-dependent biotin uptake carrier that appears to exist in the form of
      multiple variants.
FAU - Chatterjee, N S
AU  - Chatterjee NS
AD  - Medical Research Service, Veterans Affairs Medical Center, Long Beach 90822, USA.
FAU - Kumar, C K
AU  - Kumar CK
FAU - Ortiz, A
AU  - Ortiz A
FAU - Rubin, S A
AU  - Rubin SA
FAU - Said, H M
AU  - Said HM
LA  - eng
SI  - GENBANK/AF143309
SI  - GENBANK/AF143310
SI  - GENBANK/AF143311
GR  - DK-56061/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Am J Physiol
JT  - The American journal of physiology
JID - 0370511
RN  - 0 (5' Untranslated Regions)
RN  - 0 (Carrier Proteins)
RN  - 0 (DNA, Complementary)
RN  - 0 (Membrane Proteins)
RN  - 0 (RNA, Messenger)
RN  - 0 (Symporters)
RN  - 0 (biotin transporter)
SB  - IM
CIN - Am J Physiol. 1999 Oct;277(4 Pt 1):C603-4. PMID: 10516088
MH  - 5' Untranslated Regions/genetics
MH  - Animals
MH  - Base Sequence
MH  - COS Cells
MH  - Carrier Proteins/*genetics
MH  - Cloning, Molecular
MH  - DNA, Complementary/genetics/metabolism
MH  - Genetic Variation
MH  - Intestinal Mucosa/*metabolism
MH  - Membrane Proteins/*genetics
MH  - Molecular Sequence Data
MH  - Open Reading Frames
MH  - RNA, Messenger/metabolism
MH  - Rats
MH  - Reverse Transcriptase Polymerase Chain Reaction
MH  - *Symporters
MH  - Tissue Distribution
MH  - Transfection
EDAT- 1999/10/12 00:00
MHDA- 1999/10/12 00:01
CRDT- 1999/10/12 00:00
PHST- 1999/10/12 00:00 [pubmed]
PHST- 1999/10/12 00:01 [medline]
PHST- 1999/10/12 00:00 [entrez]
AID - 10.1152/ajpcell.1999.277.4.C605 [doi]
PST - ppublish
SO  - Am J Physiol. 1999 Oct;277(4):C605-13. doi: 10.1152/ajpcell.1999.277.4.C605.