Differential tissue-specific expression of neurofibromin isoform mRNAs in rat.
We have cloned the full-length cDNA encoding the rat homolog of type I neurofibromin isoform, a protein product of a gene linked to neurofibromatosis type 1. Rat type I neurofibromin isoform is composed of 2,820 amino acid residues and shares about 98.5% amino acid identity with the human counterpart. By S1 nuclease mapping analysis of the alternatively spliced neurofibromin mRNAs in adult rat tissues, we showed that type I isoform mRNA was predominantly expressed in the brain, pituitary, and testis, while type II mRNA, carrying a 63-nucleotide insertion in the region coding for the domain related to GTPase-activating protein, was predominantly expressed in most other tissues, such as heart, kidney, and ovary. Furthermore, type II mRNA is predominant in the testis at age 1 week, while type I mRNA becomes predominant at 3 weeks and is subsequently expressed at higher levels, as seen in the adult testis. In contrast, type I mRNA is the predominant form in the brain throughout the postnatal development. Thus, the relative expression levels of type I and type II mRNAs may be specific to the tissues and to the developmental stage of certain tissues.
Suzuki
H
H
Department of Applied Physiology, and Molecular Biology, Tohoku University School of Medicine, Sendai.
Takahashi
K
K
Yasumoto
K i
Ki
Fuse
N
N
Shibahara
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D025542:Neurofibromin 1; D011506:Proteins / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats
D025542:Neurofibromin 1; D011506:Proteins; D012333:RNA, Messenger