LanA transcripts are detected in 4-6hr embryos, peak at 10-12hr, and then decline. Later peaks occur in early larvae, and late pupae. Developmental increases in Laminin transcripts are associated with periods of morphogenesis and precede those of Col4a1 transcripts. Laminin transcripts appear in newly formed mesoderm and are later expressed in fat body, in some glial cells and prominantly in hemocytes found distributed around many organs where basement membrane deposition occurs such as brain, nerve cord, sensory organs, and various internal organs. LanA transcripts are detected at a lower level than LanB1 and LanB2 transcripts.

LanA expression is first detected during germ band extension in the mesoderm and at lower levels in the ectoderm including the neurogenic region. At ~8hr, the level of LanA expression dramatically increases in both the somatic and visceral mesoderm and expression in these tissues continues through the rest of embryonic development. At 8hr, expression in the ectoderm also increases but mainly in the epidermis and not in ectodermal derivatives such as the salivary glands and the CNS. The only LanA expression in the CNS is found along the midline. The interface glia were also tentatively identified as a site of LanA expression. The patterns of expression of LanA, LanB1, and LanB2 are nearly identical.

LanA transcripts are expressed through most of embryogenesis with a peak in 6-9hr embryos.

LanA starts to accumulate around the trachea at embryonic stage 14.

LanA is detected on the surface of the optic stalk surface glial cell layer.

LanA protein is detected in embryonic hemocytes and fat body. In later embryos, LanA protein is observed in basement membranes surrounding the nerve cord, brain, gut, spiracles, sensory bodies, and muscles.

In dissected embryos between 10-13 hours of development, LanA is detected in basement membrane throughout the embryo. These include basement membranes covering the inside of the epidermis, developing muscles, gut, and internal glands and organs. LanA is also detected in the dorsal basement membrane overlying the developing CNS and in a prominent pair of mesodermal cells just dorsal to the nervous system. The most striking staining in the developing CNS is seen along the axon pathways, including the longitudinal pathways, the commissural pathways, and the peripheral nerve roots. The glia around the peripheral nerve roots also stain. Staining is also observed surrounding clusters of peripheral sensory organs and their support cells. All three Laminin subunits show similar patterns of staining.