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Positional Fate Map Reveals a Unified Heart Forming Region
Author(s) -
Cui Cheng,
Little Charles D.,
Rongish Brenda J.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a200-a
Subject(s) - fate mapping , mesoderm , biology , hfr cell , heart development , primitive streak , embryo , stage (stratigraphy) , anatomy , microbiology and biotechnology , gastrulation , progenitor cell , genetics , gene , embryogenesis , stem cell , embryonic stem cell , paleontology , escherichia coli
The heart forming region (HFR) in the chick has been previously defined using: positional fate maps of mesodermal cells and expression patterns of cardiac genes, such as Nkx2.5 and Bmp‐2. Positional‐fate‐maps indicate that the primary HFRs reside in separated bilateral fields in the lateral mesoderm of the HH stage 5 embryo. On the contrary, Nkx2.5 and Bmp‐2 are expressed in a continuous arc‐shaped region expanding from one side to the other at this stage. Furthermore, studies in the past several years identified a secondary HFR in the cranial paraxial mesoderm that contributes to the rostral end of the elongating heart tube between HH stage 12 and 22. To address these discrepant results, we used time‐lapse imaging to follow heart progenitor mesodermal cells in avian embryos between HH stage 3+, when they ingress through the primitive streak, and HH stage 12, when the heart has looped. Cells were labeled with fluorescent tags at HH Stage 3–3+ using an in‐vivo electroporation technique and images were acquired at 6‐8 minute intervals. Our positional‐fate‐mapping studies reveal one continuous HFR at HH stage 5, and confirm the arc‐shaped Nkx2.5 and Bmp‐2 gene expression patterns. Furthermore, our data suggest the secondary HFR is not spatially isolated from the primary HFR. We thus present a 're‐defined' HFR and a time‐lapse analysis of the movements of mesdoermal cells as they form the heart in avian embryos. Support: G. Harold and Leila Y. Mathers Charitable Foundation (CDL and BJR) and American Heart Association Fellowship 0620105Z (CC).