tin and eya are coexpressed in the entire mesoderm at embryonic stage 8 and 9. By stage 10, tin expression is restricted to the dorsal mesoderm while eya expression is restricted to the dorsal mesoderm.

(Liu et al., 2009)

tin is first expressed between 2 and 4 hours of embryogenesis, peaks between 4 and 8 hours and decreases dramatically in late embryogenesis. It is not expressed postembryonically. tin is first expressed in the cellular blastoderm embryo in the ventral-most region of the embryo. After invagination of the ventral-most cells, tin mRNA is found exclusively in the mesoderm. During stage 9, tin expression is reduced in some mesodermal cells and by stage 10, tin expression is restricted to 6-8 cells on either side in the dorsal-most reigons of the mesoderm. During stage 11, each tin-expressing region splits into two separate domains. One corresponds to part of the visceral mesoderm and the other to cells at the dorsal tip of the mesoderm that include the precursors to the heart. tin expression continues in heart progenitors until late stages of embryogenesis when they differentiate into the dorsal blood vessel.

(Azpiazu and Frasch, 1993)

tin transcripts are expressed predominantly between 3 and 9 hours of embryogenesis and are present at low levels between 9 and 12 hours. They are first expressed along the ventral longitudinal axis in the late blastoderm just prior to the ventral invagination of the mesoderm. The strip of tin-expressing cells is about 14-16 cells wide. After gastrulation, tin is expressed in the mesoderm. At about 4.5 hours, the mesodermal mass starts to spread dorsally. As the cell layer reaches the dorsal margin, ventrally located mesodermal cells cease tin expression. The dorsally located cells which are the primordia for the visceral musculature express tin for another 1-2 hours. In stage 11, tin expression in the dorsal mesoderm is reduced to patches of cells. tin expression is also seen in the cephalic region at ~stage 10-11 surrounding the stomodeum. In stage 11, a row of cells at the dorsal margin begins expressing tin. These cells which correspond to heart primordia, are the only ones that continue to express tin after the germ band extended stage.

(Bodmer et al., 1990)

tin protein is expressed in cardial, but not pericardial, cells in third instar larvae.

(Das et al., 2008)

tin protein is observed in the cephalic vascular rudiment, a group of cells surrounding the migrating corpus cardiacum precursor cells, and that represent an evolutionary vestige of the cephalic aorta.

(De Velasco et al., 2004)

Expression of tin protein is observed in four pairs of cardioblasts per thoracic hemisegment, and in the posterior-most four pairs of cardioblasts per abdominal hemisegment.

(Perrin et al., 2004)

Four pairs of tin-positive nuclei are seen in the larval heart but none are in the region of the ostia.

(Molina and Cripps, 2001)

tin protein is detected in the trunk mesoderm at stage 8-9, the dorsal mesoderm at stage 10, and the cardiac and visceral mesoderm at stage 11-12. After stage 14, expression is restricted to the developing heart. In stage 15-16 embryos, expression is detected in the myocardial and pericardial cells of the heart tube, with only 4 out of 6 cells per hemisegment expressing tin protein.

(Venkatesh et al., 2000)