Gene and microRNA expression in p53-deficient day 8.5 mouse embryos.
BACKGROUND
Neural tube defects (NTDs) are one of the most common human birth defects, with a prevalence of approximately 1 in 1000 live births in the United States. In animal studies, deletion of p53 leads to a significant increase in embryos that exhibit exencephaly. Whereas several studies have closely investigated the morphologic changes of p53-deficient embryos, no study has reported the molecular-level alteration in p53-deficient embryos. Here we attempt to identify genes and microRNAs (miRNAs) modified by deletion of p53 in day 8.5 mouse embryos.


METHODS
Mouse embryos from p53 heterozygous crosses were collected, genotyped, and embryos of similar genotype (+/+; +/-; -/-) were pooled. RNA from the pooled samples was isolated to determine mRNA and miRNA expression levels using Whole Genome Bioarrays and Low Density Arrays, respectively.


RESULTS
In p53 -/- embryos, 388 genes showed statistically significant alteration in gene expression of more than twofold compared to p53 +/+ embryos. Expression of p53 and well known p53 target genes, such as p21 and cyclin G1, were significantly down-regulated in p53 -/- embryos. In contrast, expression of other p53 target genes, such as Mdm2, Noxa, and Puma, were unchanged. We also identified six genes (Csk, Itga3, Jarid2, Prkaca, Rarg, and Sall4), known to cause NTDs when deleted, that are also down-regulated in p53 -/- embryos. Finally, five miRNAs (mir-1, mir-30e-3p, mir-142-3p, mir-301, and mir-331) also showed statistically significant alterations in expression levels in p53 -/- embryos compared to p53 +/+ embryos. Combined analysis of the experimental data using stepwise regression model and two publicly available algorithms identified putative target genes of these miRNAs.


CONCLUSIONS
Our data have identified genes and miRNAs that may be involved in the mechanisms underlining NTDs and begin to define the developmental role of p53 in the etiology of NTDs.
Hosako
Hiromi
H
Department of Veterinary Physiology and Pharmacology, Texas A&M University, 434 VMR Building, College Station, TX 77843, USA. hhosako@cvm.tamu.edu
Martin
Gail S
GS
Barrier
Marianne
M
Chen
Yian A
YA
Ivanov
Ivan V
IV
Mirkes
Philip E
PE
D000818:Animals; D004622:Embryo, Mammalian / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D009436:Neural Tube Defects / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53
D035683:MicroRNAs; D016159:Tumor Suppressor Protein p53