The brain link protein-1 (BRAL1): cDNA cloning, genomic structure, and characterization as a novel link protein expressed in adult brain.
We report here molecular cloning and expression analysis of the gene for a novel human brain link protein-1 (BRAL1) which is predominantly expressed in brain. The predicted open reading frame of human brain link protein-1 encoded a polypeptide of 340 amino acids containing three protein modules, the immunoglobulin-like fold and proteoglycan tandem repeat 1 and 2 domains, with an estimated mass of 38 kDa. The brain link protein-1 mRNA was exclusively present in brain. When analyzed during mouse development, it was detected solely in the adult brain. Concomitant expression pattern of mRNAs for brain link protein-1 and various lectican proteoglycans in brain suggests a possibility that brain link protein-1 functions to stabilize the binding between hyaluronan and brevican. The human BRAL1 gene contained 7 exons and spanned approximately 6 kb. The entire immunoglobulin-like fold was encoded by a single exon and the proteoglycan tandem repeat 1 and 2 domains were encoded by a single and two exons, respectively. The deduced amino acid sequence of human brain link protein-1 exhibited 45% identity with human cartilage link protein-1 (CRTL1), previously reported as link protein to stabilize aggregates of aggrecan and hyaluronan in cartilage. These results suggest that brain link protein-1 may have distinct function from cartilage link protein-1 and play specific roles, especially in the adult brain.
Hirakawa
S
S
Department of Molecular Biology and Biochemistry, Okayama University Medical School, Okayama, 700-8558, Japan.
Oohashi
T
T
Su
W D
WD
Yoshioka
H
H
Murakami
T
T
Arata
J
J
Ninomiya
Y
Y
D000328:Adult; D000375:Aging / Q000235:genetics / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D058581:Brevican; D011508:Chondroitin Sulfate Proteoglycans / Q000378:metabolism; D003001:Cloning, Molecular; D005091:Exons / Q000235:genetics*; D016326:Extracellular Matrix Proteins; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D006820:Hyaluronic Acid / Q000378:metabolism; D007438:Introns / Q000235:genetics*; D037181:Lectins, C-Type; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry; D011509:Proteoglycans / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D016415:Sequence Alignment; D000099249:Proteoglycan Link Protein
D058581:Brevican; D011508:Chondroitin Sulfate Proteoglycans; D016326:Extracellular Matrix Proteins; D006820:Hyaluronic Acid; D037181:Lectins, C-Type; D009419:Nerve Tissue Proteins; D011506:Proteins; D011509:Proteoglycans; D012333:RNA, Messenger; D000099249:Proteoglycan Link Protein; C546938:BCAN protein, human; C553057:Bcan protein, mouse; C415863:HAPLN2 protein, human; C485934:Hapln2 protein, mouse