Fibulin-2 (FBLN2): human cDNA sequence, mRNA expression, and mapping of the gene on human and mouse chromosomes.
Fibulin-2 is a new extracellular matrix protein that we recently identified by characterizing mouse cDNA clones. Fibulin-2 mRNA is prominently expressed in mouse heart tissue and is present in low amounts in other tissues. In this study, we isolated and sequenced a 4.1-kb human fibulin-2 cDNA, which encoded a mature protein of 1157 amino acids preceded by a 27-residue signal sequence. The predicted polypeptide contains three consecutive anaphylatoxin-related segments (domain I) in its central region followed by 10 EGF-like repeats (domain II), 9 of which have a consensus sequence for calcium binding. The 408-residue N-terminal region consists of two separate subdomains, a cysteine-rich segment of 150 residues (Na subdomain) and a cysteine-free segment with a stretch of acidic amino acids (Nb subdomain). The 115-residue C-terminal segment (domain III) is similar to the C variant of fibulin-1. The amino acid sequences of the human and mouse fibulin-2 share approximately 90% identity in domains Na, I, II, and III but only 62% identity in domain Nb. The human cDNA lacks an EGF-like repeat, which is alternatively spliced in the mouse cDNA clones, and a potential cell-binding Arg-Gly-Asp sequence found in the Nb domain of the mouse counterpart. Northern blot analysis of mRNA from various human tissues reveals an abundant 4.5-kb transcript in heart, placenta, and ovary tissue. The expression pattern differs from that of fibulin-1. The fibulin-2 gene was localized by in situ hybridization to the p24-p25 region of human chromosome 3 and to the band D-E of mouse chromosome 6.
Zhang
R Z
RZ
Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Pan
T C
TC
Zhang
Z Y
ZY
Mattei
M G
MG
Timpl
R
R
Chu
M L
ML
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D002874:Chromosome Mapping; D002893:Chromosomes, Human, Pair 3; D016384:Consensus Sequence; D018076:DNA, Complementary / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis / Q000235:genetics*; D015870:Gene Expression; D005796:Genes; D006801:Humans; D007223:Infant; D051379:Mice / Q000235:genetics*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D013045:Species Specificity
D002135:Calcium-Binding Proteins; D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins; D012333:RNA, Messenger; C084612:fibulin 2