Cross-regulatory interactions between bithorax complex genes

Cross-regulatory interactions between bithorax complex genes, specifying thoracic and abdominal segment fates Cross-regulatory interactions between bithorax complex genes, specifying thoracic and abdominal segment fates

(a) Wild type Parasegments 3 4 5 , 7 91011121314 Abdominal-B (Abd—B. blue) abdominal-A (abd-A; green) Ulo'abithorax (be; red) T1 T2 T3 A1 A2A3MASA6A7A8 Segments ’ Both um and abd-A have a diffuse posterior boundary of expression " due to negative regulatory interactions between genes. (b) Loss of be 3 4 4 4 7 1011121314 Abdominal-B abdominal-A T1 T2 T2 T2 “A2 A3 A4 A5 A6 A7A8 T3 and A1 are incorrectly speofied as T2 due to a failure to repress Antennapedia in these segments. (c) Loss of all bithorax complex (be, abd—A, and Abd—B) 3444444444414 T1 T2 T2 T2 T2 T2 T2 T2 T2 T2T2 All segments posterior to T1 differentiate as T2 due to a failure to repress Antennapedia in all posterior segments. (d) Loss of abd-A and Abd-B 3456666666614 Ultrabi thorax T1 T2 T3 A1 A1 A1 A1 A1 A1 MN I All abdominal segments differentiate as A1 due to failure x of abd-A and Abd-B to repress be expression in posterior segments. (e) Loss of Abd—B 3 456789999914 abdominal-A Ultrabithorax T1 T2 T3 A1 A2 A3 A4 A4 A4 A4A4 to loss of repression byAbd«B, leading to most posterior I be and abd-A are both expressed more posteriorly due \ abdominal segments differentiating as A4.