expression begins to appear in sens
-positive photoreceptor neuron precursors (Bolwig organ primordium) in early stage 12, at which time sens
expression is weakening. Expression continues through stage 15.
proteins are predominantly nuclear.
is expressed in a subtype-specific fashion in the larval eye. In embryos, it is expressed in 3-4 immature photoreceptor cells. In the larva, it is expressed in the R5-specific photoreceptors of the Bolwig organ and is excluded from the R6 photoreceptors.
Expression in the anterior compartment is low. Expression is high in the posterior compartment which corresponds to veins L3 and L4. sal
wing blade-specific enhancer that includes the information required to generate the salm
expression domain in the wing.
Larval expression of salm
protein is observed in photoreceptor cells R3 and R4 starting in row 3 and progressively fading between rows 7 and 11, in photoreceptor cell R7 starting in row 9, in photoreceptor cell R8 starting in row 11, in the anterior and posterior cone cells starting in row 11, and the four cone cells by row 14-15. By 24 hours pupariation, salm
protein continues to be expressed in photoreceptor cells R7 and R8.
The pattern ofexpression of the Spalt proteins, products of salm
, are restricted to the medial portion of the dorsal compartment of the wing disc during third instar.
is expressed in non-neuronal cells of the Lch5.
protein is expressed in the central region of the wing pouch flanking the anterior-posterior boundary.
protein expression patterns were compared. The proteins have identical staining patterns in the wing imaginal disc (FBrf0087811
) but have different patterns in the embryonic CNS and spiracles. salr
is more abundant in the embryonic brain, while salm
is more abundant in the posterior spiracle. The two proteins have overlapping but non-identical patterns in the ventral cord.
transcripts and proteins are distributed in identical patterns in the third larval instar wing disc. In late third instar larval discs, expression is detected in a band perpendicular to the dorsoventral boundary.
In late stage 4embryos, salm
protein is detected in a circumferential band at about60-70% egg length. This stripe persists into the cellular blastoderm stage(stage 5), when salm
protein accumulation is seen in two additionalregions, at 12-20% egg length, and 80-86% egg length. salm
transcriptand protein expression patterns in the cellular blastoderm stage embryothus overlap. At the extended germ band stage (stage 11), salm
proteinaccumulates in the neurectoderm in a segmental pattern. Colocalizationstudies with en
protein indicate that, although salm
proteinexpression is strongest in parasegments 1 to 3, and again in parasegments14 and 15, some weak expression is also seen in parasegment 4. In stage 15to 17 embryos, salm
protein is present in the central nervous system, aswell as the tracheal system.