The heart LIM protein gene (Hlp), expressed in the developing and adult heart, defines a new tissue-specific LIM-only protein family.
In a subtraction designed to identify transcripts accompanying mesodermal lineage specification in mouse ES differentiation cultures, we identified a gene encoding a two LIM-domain protein which we named heart LIM protein (Hlp). Hlp is most closely related to thymus LIM protein, and these two genes comprise a new gene family related to the cysteine-rich protein (CRP) gene family. In the embryo, Hlp expression is primarily restricted to the developing heart. In situ hybridization showed expression at E7.75 in the paired heart-forming primordia prior to linear heart-tube formation. At E8.5, strong expression is detected in the heart, with equal expression in both heart chambers. Hlp expression is detected in both myocardium and endocardium, and in vascular endothelium. Later in fetal development low levels of Hlp expression are detected outside the heart, including dorsal root ganglia and the spinal cord. In the adult, Hlp is expressed at highest levels in the heart, and at lower levels in the brain, skeletal muscle and aorta. Hlp expression is unchanged in hypertrophic hearts induced by aortic constriction. These data suggest a role for the two LIM-domain gene Hlp in the very earliest stages of heart differentiation and development.
Yu
Tzong-Shiue
TS
Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas 75390, USA.
Moctezuma-Anaya
Miriam
M
Kubo
Atsushi
A
Keller
Gordon
G
Robertson
Scott
S
D000595:Amino Acid Sequence; D000818:Animals; D004730:Endothelium, Vascular / Q000196:embryology / Q000378:metabolism; D005318:Fetal Heart / Q000196:embryology* / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D060588:LIM Domain Proteins; D051379:Mice; D008969:Molecular Sequence Data; D009206:Myocardium / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics*; D010802:Phylogeny; D011506:Proteins; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
C486177:Csrp1 protein, mouse; D060588:LIM Domain Proteins; D009687:Nuclear Proteins; D011506:Proteins; C074370:cysteine-rich protein, mammalian