The γ3 chain of laminin is widely but differentially expressed in murine basement membranes: Expression and functional studies

Abstract

Laminins are heterotrimeric extracellular glycoproteins found in, but not confined to, basement membranes (BMs). They are important components in formation of the molecular networks of BMs as well as in cell polarity, cell differentiation and tissue morphogenesis. Each laminin is composed by an α, a β and a γ chain. Previous studies have shown that the γ3 chain is partnered with either the β1 chain (in placenta) or β2 chain (in the CNS) (Libby et al., 2000). Several studies, including our own, suggested that the γ3 chain is expressed in both apical and basal compartments (Gersdorff et al., 2005; Koch et al., 1999; Yan and Cheng, 2006). This study investigates the expression pattern of the γ3 chain in mouse. We developed three new γ3-reactive antibodies, and we show that the γ3 chain is present in BMs. The distribution pattern is considerably more restricted than that of the γ1 chain and within any tissue there is differential deposition into BM compartments. This is particularly true in the retina and brain, where γ3 is uniquely expressed in a subset of the vascular basement membranes and the pial surface. We used conventional genetic ablation techniques to remove the γ3 chain in mice; unlike other laminin null mice (α5, β2, γ1 nulls) (Miner et al., 1998; Noakes et al., 1995; Smyth et al., 1999), these mice live a normal lifespan and have only minor abnormalities, the most striking of which are ectopic granule cells in the cerebellum and an apparent increase in capillary branching in the outer retina. These data support the suggestion that the γ3 chain is deposited in BMs and contributes some unique properties to their function, particularly in the nervous system.

Laminins containing the β2 and γ3 chains regulate astrocyte migration and angiogenesis in the retina

“…Targeted deletion of Lamb2 and Lamc3 genes and the production of the Lamb2 −/− Lamc3 −/− animals have been described previously (Noakes et al, 1995;Li et al, 2012;Dénes et al, 2007;Pinzón-Duarte et al, 2010 …”

“…Next, sections were incubated with primary antibodies (in 5% goat or donkey serum; 0.01% Triton X-100; PBS) for 48 hours at 4°C, washed and incubated with secondary antibodies. Radial sections were prepared according to our previously published methods (Li et al, 2012;Pinzón-Duarte et al, 2010).…”

“…Goat anti-rabbit 488 and 568, goat anti-rat 488 and 568, donkey anti-rabbit 488 and 594, and donkey anti-rat 488 and 594 (Life Technologies, Grand Island, NY, USA) secondary antibodies were used. The specificity of the laminin antibodies has been published previously: anti-β2 (Pinzón-Duarte et al, 2010;Radner et al, 2013) and anti-γ3 antibodies (Li et al, 2012). The following laminins were used: EHS-laminin (Life Technologies), recombinant laminin-521 (BioLamina, Stockholm, Sweden) and laminin 5 (a gift from Dr Manuel Koch, Universität zu Köln, Germany).…”

Mapping the Extracellular and Membrane Proteome Associated with the Vasculature and the Stroma in the Embryo

“…It is also found in other tissues, such as skin, heart, lung, and the reproductive tracts, and is a prominent element of the apical surfaces found on ciliated epithelial cells. It has been detected in the retinal vasculature and is thought to play an important role in vessel development (55). LAMC3 has not yet been described in the liver but could be present in liver basement membranes or in the liver vasculature.…”

Laminins and retinal vascular development

“…One study looked at laminin γ3 in the mouse retina 21 . This chain is most prominent in Bruch’s membrane and vascular basement membranes but also detected in the ILM and a subpopulation of amacrine cells.…”