Antibody:

anti alpha-actinin (EA-53)

Structure	Cell Type	Level	Pattern	Image	Note
TS12: cardiac muscle tissue	cardiac muscle cell	Present		6_E8-8.5 alpha-actinin , 6_E8-8.5 merge	Sarcomeric alpha-actinin (Actn2) is a marker for myofibril assembly. In cardiac myocytes staining was detected as periodic dots. Tmod1 immunostaining was observed between the dots.

Structure	Cell Type	Level	Pattern	Image	Note
TS15: cardiac muscle tissue	cardiac muscle cell	Present		6_E9.5 alpha-actinin , 6_E9.5 merge	Immunopositive striations alternated with Tmod1 striations.

Structure	Cell Type	Level	Pattern	Image	Note
TS20: cardiac muscle tissue	cardiac muscle cell	Present		6_E12.5 alpha-actinin , 6_E12.5 merge	Immunopositive striations were organized in a relatively mature pattern.

Structure	Cell Type	Level	Pattern	Image	Note
TS12: cardiac muscle tissue	cardiac muscle cell	Present		8_E8-8.5 merge +/+ , 8_E8-8.5 alpha-actinin +/+	Staining was observed in myofibrils of varying stages of maturity, including nascent myofibrils with irregular and/or periodic dots of immunostaining with continuous F-actin staining. Mature, but very thin, myofibrils were also present at this stage, with regularly spaced dots of immunostaining alternating with distinct and periodic gaps in F-actin.

Structure	Cell Type	Level	Pattern	Image	Note
TS12: cardiac muscle tissue	cardiac muscle cell	Present		8_E8-8.5 alpha-actinin -/- , 8_E8-8.5 merge -/-	In the mutant, periodic dots of immunostaining were frequently observed along structures with continuous F-actin staining, but distinct gaps in F-actin staining were never observed. Aggregates of Actn2 and F-actin that did not colocalize were present in some regions of the cells.

Structure	Cell Type	Level	Pattern	Image	Note
TS15: cardiac muscle tissue	cardiac muscle cell	Present		8_E9.5 alpha-actinin +/+ , 8_E9.5 merge +/+	Myofibrils exhibited regular Actn2 striations characteristic of mature Z discs, along with a striated F-actin staining pattern with gaps.

Structure	Cell Type	Level	Pattern	Image	Note
TS15: cardiac muscle tissue	cardiac muscle cell	Present		8_E9.5 alpha-actinin -/- , 8_E9.5 merge -/-	In the Tmod1 null E9.5 embryos, no striated myofibrils could be found, and nascent myofibril-like structures with dots of Actn2 staining were rarely observed. Instead, most Actn2 and F-actin appeared to be disorganized and to have accumulated into large aggregates.