Expression of <i>ISL1</i> and <i>GATA4</i> transcripts in the human heart between 26 and 38 days of gestation.

Abstract

<p><b>A–H</b>: <i>ISL1 in situ</i> at Carnegie stages (CS)12 (26–28 days post fertilization [dpf]), CS13 (28–31 dpf), CS14 (32–33 dpf) and CS15 (34–36 dpf) respectively. <b>E–H</b> are magnifications of <b>A–D</b> respectively. <b>I–K</b> show <i>GATA4</i> expression in adjacent sections to <b>B–D</b>. <b>A</b>: <i>ISL1</i> is expressed at CS12 in foregut endoderm, splanchnic mesoderm, and early motoneurons. <b>B, F</b>: At CS13, <i>ISL1</i> is transcribed by mesenchyme around the cardiac OFT and pharyngeal arches. <i>ISL1</i> expression continues in the splanchnic mesoderm between the trachea and OFT, and is visible in dorsal root ganglia, at CS14 (<b>C, G</b>) and CS15 (<b>D, H</b>). <b>I–K</b>: <i>GATA4</i> is expressed in the endocardium and myocardium of the arterial pole at CS13, CS14 and CS15 (<b>I, J, K</b> respectively). <b>Inset</b>: RT-PCR of <i>ISL1</i>, <i>GATA4</i>, <i>GATA5</i>, <i>GATA6</i>, <i>FGF10</i> and positive control <i>ACTB</i> mRNAs in embryonic human hearts at stages CS13-16 (to 40 dpf). Abbreviations: drg, dorsal root ganglia; es, esophagus; fb, forebrain; fg, foregut; ph, pharynx; nt, neural tube; oft, OFT; ra, right atrium; t, trachea. Arrows, motoneurons. Bar: 110 µm (A–D, I) and 55 µm (E–H, J, K).</p