CHARACTERIZATION OF A 2ND HUMAN CLATHRIN HEAVY-CHAIN POLYPEPTIDE GENE(CLH-22) FROM CHROMOSOME 22Q11

We report cloning and characterization of the second human clathrin he avy chain polypeptide gene (CLH-22) localized to chromosome 22q11, Hen ce H. sapiens is the first species for which two clathrin heavy chain genes have been reported, We provide 5470 bp cDNA sequence covering th e entire open reading frame of the CLH-22 gene, The predicted polypept ide is composed of 1640 amino acids. Its 6 kb transcript is expressed in all of 16 tested human tissues, suggesting it is a housekeeping gen e, Skeletal muscle, testis and heart show significantly higher express ion levels, Compared to the previously characterized human ciathrin he avy chain gene localized on chromosome 17 (CLH-17), CLH-22 shows diffe rent transcript size and expression profile in human tissues, Northern analysis of CLH-22 suggests that several alternatively spliced transc ripts exist, A presumably single, 171 bp long alternatively spliced ex on has been characterized, Amino acid sequence comparison between CLH- 22 and CLH-17 shows an overall identity and similarity of 84.7 and 91. 1%, respectively, At the nucleic acid level, identity between open rea ding frames of both genes is 74.3%, Sequence comparison with previousl y cloned genes in other species suggests that counterparts of the CLH- 17 gene have been cloned in B. taurus and R. norvegicus, whereas presu mptive mammalian homologues of the CLH-22 gene are yet to be character ized, Our Northern and Southern blot analyses of meningiomas clearly s uggest the CLH-22 gene may be involved in the tumor development and ca n be considered as a candidate for a tumor suppressor.