Selective developmental regulation of gene expression for insulin-like growth factor-binding proteins in mouse spinal cord.
METHODS
Prospective, randomized experimental study in mice.


OBJECTIVE
To determine whether insulin-like growth factor binding proteins (IGFBPs) are present in mouse spinal cord and, if so, what role they play in its development.


BACKGROUND
Insulin-like growth factors are well recognized hormonal effectors of growth hormone and are expressed in the mammalian spinal cord. The IGFBPs are a group of six genetically distinct proteins that bind IGFs and modulate their bioactivity. They appear in the brain during development, localize to the neuromuscular junction, and promote motor neuron survival. The benefit of IGF-I in amyotrophic lateral sclerosis ALS and its potential use in preventing motor neuron apoptosis in spinal cord injury dictates that studies of the presence and response of IGFBPs in that tissue be performed.


METHODS
The IGFBPs in mouse spinal cord were analyzed by Western ligand blot, Western immunoblot, and reverse transcription-polymerase chain reaction at various time points from embryonic day 14 to postnatal day 30.


RESULTS
Three IGFBPs with molecular masses of 24, 28, and 32 kDa were found, the latter two being the most prominent. The data indicate that these are IGFBP-4, -5, and -2.


CONCLUSIONS
Both IGFBP-2 and BP-5 are developmentally regulated in mouse spinal cord, with higher levels of those at early embryonic stages indicating their potential role in development of the mouse spinal cord.
Arnold
P M
PM
Neurobiology Research and Spinal Cord Research Laboratories, Department of Veterans Affairs Medical Center, Kansas City, Missouri, USA. parnold@kumc.edu
Ma
J Y
JY
Citron
B A
BA
Zoubine
M N
MN
Festoff
B W
BW
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D015153:Blotting, Western; D017931:DNA Primers / Q000737:chemistry; D004622:Embryo, Mammalian / Q000378:metabolism; D005314:Embryonic and Fetal Development; D018507:Gene Expression Regulation, Developmental; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000235:genetics* / Q000378:metabolism; D018975:Insulin-Like Growth Factor Binding Protein 5 / Q000235:genetics* / Q000378:metabolism; D008024:Ligands; D051379:Mice; D008807:Mice, Inbred BALB C; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000196:embryology* / Q000254:growth & development* / Q000378:metabolism
D017931:DNA Primers; D018971:Insulin-Like Growth Factor Binding Protein 2; D018975:Insulin-Like Growth Factor Binding Protein 5; D008024:Ligands; D012333:RNA, Messenger