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| A TRUNCATED LAMININ CHAIN HOMOLOGOUS TO THE B2 CHAIN - STRUCTURE, SPATIAL EXPRESSION, AND CHROMOSOMAL ASSIGNMENT |
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| Author(s): KALLUNKI P, SAINIO K, EDDY R, BYERS M, KALLUNKI T, SARIOLA H, BECK K, HIRVONEN H, SHOWS TB, TRYGGVASON K |
| Source: JOURNAL OF CELL BIOLOGY Volume: 119 Issue: 3 Pages: 679-693 Published: NOV 1992 |
| Times Cited: 215 References: 74 |
| Abstract: We describe the identification of a novel laminin chain. Overlapping clones were isolated from a human fibrosarcoma HT1080 cell cDNA library spanning a total of 5,200 bp. A second set of clones contained an alternative 3' end sequence giving a total of 4,316 bp. The longer sequence contained an open reading frame for a 1,193-residue-long polypeptide. The alternative sequence was shortened at the carboxyl-terminal end coding for a 1,111-residue-long polypeptide. The amino acid sequence contained 21 amino acids of a putative signal peptide and 1,172 residues or alternatively 1,090 residues of a sequence with five distinct domains homologous to domains I-V in laminin chains. Comparison of the amino acid sequences showed that the novel laminin chain is homologous to the laminin B2 chain. However, the structure of the novel laminin chain isolated here differs significantly from that of the B2 chain in that it has no domain VI and domains V, IV, and III are shorter, resulting in a truncated laminin chain. The alternative sequence had a shortened domain I/II. In accordance with the current nomenclature, the chain characterized here is termed B2t. Calculation of possible chain interactions of laminin chains with the B2t chain domain I/II indicated that the B2t chain can replace the B2 chain in some laminin molecules. The gene for the laminin B2t chain (LAMB2T) was localized to chromosome 1q25-q31 in close proximity to the laminin B2 chain gene. Northern analysis showed that the B2t chain is expressed in several human fetal tissues but differently from the laminin B1 and B2 chains. By in situ hybridization expression of the B2t chain was localized to specific epithelial cells in skin, lung, and kidney as opposed to a general epithelial and endothelial cell expression of the laminin B2 chain in the same tissues. |
| Document Type: Article |
| Language: English |
| Reprint Address: KALLUNKI, P (reprint author), UNIV OULU, BIOCTR, SF-90570 OULU, FINLAND |
Addresses:
1. UNIV OULU, DEPT BIOCHEM, SF-90570 OULU, FINLAND
2. UNIV HELSINKI, DEPT PATHOL, SF-00100 HELSINKI 10, FINLAND
3. NEW YORK STATE DEPT HLTH, ROSWELL PK MEM INST, DEPT HUMAN GENET, BUFFALO, NY 14263 USA
4. UNIV LINZ, INST BIOPHYS, A-4040 LINZ, AUSTRIA
5. UNIV TURKU, DEPT MED BIOCHEM, SF-20500 TURKU 50, FINLAND |
| Publisher: ROCKEFELLER UNIV PRESS, 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 |
| Subject Category: Cell Biology |
| IDS Number: JV269 |
| ISSN: 0021-9525 |
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