Mutant embryos are characterized by detached alary muscles and an irregular morphology of the dorsal vessel, while muscle fibers in the body wall musculature show only mild defects and visceral muscles are barely affected.

The close association of pericardial cells with the myocardial tube is weakened in LanB1^S0733 embryos and, as muscle contraction begins, pericardial cells contacted by alary muscles eventually get pulled away.

Cardiomyocytes in LanB1^S0733 or LanB1^S0733/Df(2L)ED12527 embryos are misaligned along the dorsal vessel, with occasional gaps or single-rowed stretches accompanied by denser spacing of cells. Cell polarization is not generally disturbed. The normal formation of a ventricle with a wide lumen does not occur in these mutants - areas forming a small lumen alternate with collapsed portions in both parts of the dorsal vessel.

Formation of a contiguous ECM later is abolished pre-dominantly around the heart tube in LanB1^S0733 mutant embryos.

Col4a1^S3064, LanB1^S0733 has partially lethal - majority die phenotype

LanB1^S0733 has larval pericardial cell phenotype, suppressible by org-1^OJ487