In situ-RT-PCR and immunohistochemistry for the localisation of the mRNA of the alpha 3 chain of laminin and laminin-5 during human organogenesis.
Laminin-5 is known to be an integral part of the hemidesmosome and therefore responsible for the integrity of the connection of the epithelium to the basement membrane. This is also an important mechanism during embryonic development, as documented by studies in mice. In an attempt to elucidate its implication for human development we localised the mRNA of the alpha3 chain of laminin with the help of in situ RT-PCR, and the laminin-5 protein immunohistochemically. We systematically investigated kidney, lung, skin and intestinal tissue of consecutive developmental stages during human embryogenesis. From gw 6.5 onwards, the mRNA of the alpha3 chain of laminin was found exclusively in the cytoplasm of epithelial cells of the developing kidney, lung, skin and intestine. Interestingly, in the skin and intestine from gw 8 onwards, the superficial cell layers also stained positive for the mRNA, while the protein was still only found in the dermal-epidermal and enteric basement membrane zones. In all developing organs investigated, the mRNA of the alpha3 chain of laminin is strictly of epithelial origin and the corresponding protein localised in the underlying basement membrane zones. Due to this discrepancy, we postulate a broader role for laminin-5 during human embryogenesis, for example, for epithelial cell development, beyond its involvement in hemidesmosome formation and cell adhesion.
Miosge
Nicolai
N
Department of Histology, University of Göttingen, Kreuzbergring 36, 37075 Göttingen, Germany. nmiosge@gwdg.de
Kluge
Jens-Gerrit Alexander
JG
Studzinski
Arthur
A
Zelent
Christina
C
Bode
Christa
C
Sprysch
Patricia
P
Burgeson
Robert E
RE
Herken
Rainer
R
D000328:Adult; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000235:genetics; D005333:Fetus; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007150:Immunohistochemistry; D007422:Intestines / Q000737:chemistry / Q000196:embryology / Q000502:physiology; D007668:Kidney / Q000737:chemistry / Q000196:embryology / Q000502:physiology; D007797:Laminin / Q000032:analysis* / Q000235:genetics*; D008168:Lung / Q000737:chemistry / Q000196:embryology* / Q000502:physiology; D038081:Organogenesis / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012867:Skin / Q000737:chemistry / Q000196:embryology; D000097794:Kalinin
D015815:Cell Adhesion Molecules; D007797:Laminin; D012333:RNA, Messenger; D000097794:Kalinin; C095567:laminin alpha 3