One of the tightly clustered genes of the XXXX surfeit locus is a highly expressed member of a multigene family whose other members are predominantly processed pseudogenes.

@entity71147 @entity1522 @entity19 @entity71144 @entity534 @entity71146 @entity71148 @entity71145
The @entity19 surfeit locus is unusual in that it contains a number of closely clustered genes ( @entity71144 ) that alternate in their direction of transcription (T. Williams, J. Yon, C. Huxley, and M. Fried, Proc. Natl. Acad. Sci. USA 85:3527-3530, 1988). The heterogeneous 5' ends of @entity71145 and @entity71146 are separated by 15 to 73 base pairs (bp), and the 3' ends of @entity71146 and @entity71147 overlap by 133 bp (T. Williams and M. Fried, Mol. Cell. Biol. 6:4558-4569, 1986; T. Williams and M. Fried, Nature (London) 322:275-279, 1986). A fourth gene in this locus, @entity71148 , which is a member of a multigene family, has been identified. The poly(A) addition site of @entity71148 lies only 70 bp from the poly(A) addition site of @entity71145 . Transcription of @entity71148 has been studied in the absence of the other members of its multigene family after transfection of a cloned genomic @entity19 DNA fragment, containing the @entity71148 gene, into heterologous monkey cells. @entity71148 specifies a highly expressed 1.0-kilobase mRNA that contains a long open reading frame of 266 @entity1522 , which would encode a highly basic polypeptide (23% @entity534 plus Lys). The other members of the @entity71148 multigene family are predominantly, if not entirely, intronless pseudogenes with the hallmarks of being generated by reverse transcription. The role of the very tight clustering on regulation of expression of the genes in the surfeit locus is discussed.
