Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
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Target Concepts:
Gene/Protein
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Query: EC:3.1.26.9 (
ribonuclease
)
6,589
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
LIM homeodomain transcription factors play crucial roles in determining diverse aspects of neuronal development both in vertebrates and invertebrates. In the present study, we studied the expression pattern of
Islet-1
(
Isl-1
), a member of the LIM homeodomain protein family, in the rat striatum during development. The developmental expression of
Isl-1
in the striatum is highly dynamic and complex in terms of spatial and temporal regulation. The reverse transcription-polymerase chain reaction and
ribonuclease
protection assays demonstrated that
Isl-1
messenger RNA was expressed in the developing striatum. The immunocytochemical study of
Isl-1
protein expression showed that there were prominent mediolateral and caudorostral
Isl-1
gradients in the developing striatum. Numerous
Isl-1
-positive cells appeared in the medial mantle zone of the developing striatal proper, and they co-expressed the postmitotic neuronal marker, microtubule-associated protein 2. The numbers of
Isl-1
-positive cells were decreased from the medial to the lateral regions, so that there were only a few
Isl-1
-positive cells scattered in the lateral striatum. These scattered
Isl-1
-positive cells were doubly labeled with tyrosine kinase receptor A and choline acetyltransferase, which indicated that they were cholinergic neurons. The
Isl-1
gradients were most prominent in the embryonic day 18 and 20 striatum. With increases of time, the
Isl-1
gradients were gradually reduced, and the gradients disappeared by postnatal day 7. Despite the general down-regulation of striatal
Isl-1
, a few
Isl-1
-positive cells were sustained into the adult striatum in which
Isl-1
was nearly exclusively expressed by all cholinergic neurons and vice versa. Our study suggests that
Isl-1
is likely to be initially expressed by postmitotic cholinergic precursors and some, if not all, non-cholinergic precursors in the developing striatum. During the progression of striatal differentiation,
Isl-1
is down-regulated in non-cholinergic cells, but is sustained in cholinergic cells. The developmental restriction of
Isl-1
to cholinergic neurons in the striatum may represent a novel mechanism by which LIM homeodomain proteins specify specific cell types in the striatum during development.
...
PMID:Developmental restriction of the LIM homeodomain transcription factor Islet-1 expression to cholinergic neurons in the rat striatum. 1130 Dec 7
