A hypomorphic vasopressin allele prevents anxiety-related behavior.
BACKGROUND
To investigate neurobiological correlates of trait anxiety, CD1 mice were selectively bred for extremes in anxiety-related behavior, with high (HAB) and low (LAB) anxiety-related behavior mice additionally differing in behavioral tests reflecting depression-like behavior.


RESULTS
In this study, microarray analysis, in situ hybridization, quantitative real-time PCR and immunohistochemistry revealed decreased expression of the vasopressin gene (Avp) in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei of adult LAB mice compared to HAB, NAB (normal anxiety-related behavior) and HABxLAB F1 intercross controls, without detecting differences in receptor expression or density. By sequencing the regions 2.5 kbp up- and downstream of the Avp gene locus, we could identify several polymorphic loci, differing between the HAB and LAB lines. In the gene promoter, a deletion of twelve bp Delta(-2180-2191) is particularly likely to contribute to the reduced Avp expression detected in LAB animals under basal conditions. Indeed, allele-specific transcription analysis of F1 animals revealed a hypomorphic LAB-specific Avp allele with a reduced transcription rate by 75% compared to the HAB-specific allele, thus explaining line-specific Avp expression profiles and phenotypic features. Accordingly, intra-PVN Avp mRNA levels were found to correlate with anxiety-related and depression-like behaviors. In addition to this correlative evidence, a significant, though moderate, genotype/phenotype association was demonstrated in 258 male mice of a freely-segregating F2 panel, suggesting a causal contribution of the Avp promoter deletion to anxiety-related behavior.


CONCLUSIONS
Thus, the identification of polymorphisms in the Avp gene promoter explains gene expression differences in association with the observed phenotype, thus further strengthening the concept of the critical involvement of centrally released AVP in trait anxiety.
Max Planck Institute of Psychiatry, Munich, Germany.
Mirjam
M
Bunck
Ludwig
L
Czibere
Charlotte
C
Horvath
Cornelia
C
Graf
Elisabeth
E
Frank
Melanie S
MS
Kessler
Chris
C
Murgatroyd
Bertram
B
Müller-Myhsok
Mariya
M
Gonik
Peter
P
Weber
Benno
B
Pütz
Patrik
P
Muigg
Markus
M
Panhuysen
Nicolas
N
Singewald
Thomas
T
Bettecken
Jan M
JM
Deussing
Florian
F
Holsboer
Dietmar
D
Spengler
Rainer
R
Landgraf
D000483:Alleles; D000818:Animals; D001007:Anxiety / Q000235:genetics* / Q000503:physiopathology; D001127:Arginine Vasopressin / Q000235:genetics* / Q000378:metabolism; D001522:Behavior, Animal / Q000502:physiology*; D003863:Depression / Q000235:genetics / Q000503:physiopathology; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000502:physiology; D009483:Neuropsychological Tests; D020411:Oligonucleotide Array Sequence Analysis; D010121:Oxytocin / Q000235:genetics / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D013495:Supraoptic Nucleus / Q000378:metabolism
D001127:Arginine Vasopressin; D010121:Oxytocin