LanB1 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.

LanB1 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 LanB1 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 LanB1 expression in the CNS is found along the midline. The interface glia were also tentatively identified as a site of LanB1 expression. The patterns of expression of LanA, LanB1, and LanB2 are nearly identical.

LanB1 transcripts are expressed through most of embryogenesis with a peak in 6-9hr embryos.

LanB1 was detected in the basement membranes of most embryonic tissues such as muscles and gut and is enriched at muscle attachment sites. It is prominently expressed in basement membranes of wing discs during larval and pupal development. In third instar larvae and early pupal stages, it is present on the basal side of the epithelium and colocalizes with integrins. It later localizes to the basal side of the lacuna formed after apposition of dorsal and ventral wing surfaces. It is later observed in developing longitudinal veins while integrins are found in the intervein regions.

In embryos, LanB1 protein is detected in fat body, in hemocytes and in basement membranes surrounding many tissues.

In dissected embryos between 10-13 hours of development, LanB1 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.