Analysis of the human neurexin genes: alternative splicing and the generation of protein diversity.
The neurexins are neuronal proteins that function as cell adhesion molecules during synaptogenesis and in intercellular signaling. Although mammalian genomes contain only three neurexin genes, thousands of neurexin isoforms may be expressed through the use of two alternative promoters and alternative splicing at up to five different positions in the pre-mRNA. To begin understanding how the expression of the neurexin genes is regulated, we have determined the complete nucleotide sequence of all three human neurexin genes: NRXN1, NRXN2, and NRXN3. Unexpectedly, two of these, NRXN1 ( approximately 1.1 Mb) and NRXN3 ( approximately 1.7 Mb), are among the largest known human genes. In addition, we have identified several conserved intronic sequence elements that may participate in the regulation of alternative splicing. The sequences of these genes provide insight into the mechanisms used to generate the diversity of neurexin protein isoforms and raise several interesting questions regarding the expression mechanism of large genes.
Rowen
Lee
L
Institute for Systems Biology, 1441 North 34th Street, Seattle, Washington 98103, USA.
Young
Janet
J
Birditt
Brian
B
Kaur
Amardeep
A
Madan
Anup
A
Philipps
Dana L
DL
Qin
Shizhen
S
Minx
Patrick
P
Wilson
Richard K
RK
Hood
Leroy
L
Graveley
Brenton R
BR
D017398:Alternative Splicing / Q000235:genetics*; D001483:Base Sequence; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics*; D019006:Neural Cell Adhesion Molecules / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
D009419:Nerve Tissue Proteins; D019006:Neural Cell Adhesion Molecules