tailieunhanh - Báo cáo khoa học: Characterization of sequence variations in human histone H1.2 and H1.4 subtypes

In humans, eight types of histone H1 exist (–, H1 , H1t and H1oo), all consisting of a highly conserved globular domain and less con-served N- and C-terminal tails. Although the precise functions of these iso-forms are not yet understood, and H1 subtypes have been found to be dispensable for mammalian development, it is now clear that specific func-tions may be assigned to certain individual H1 subtypes. | ềFEBS Journal Characterization of sequence variations in human histone and subtypes Bettina Sarg1 Anna Green2 Peter Soderkvist2 Wilfried Helliger1 Ingemar Rundquist2 and Herbert H. Lindner1 1 Division of ClinicalBiochemistry Biocenter Innsbruck MedicalUniversity Austria 2 Division of Cell Biology Linkopings Universitet Sweden Keywords HILIC linker histones sequence variants SNP tumor cell lines Correspondence H. H. Lindner Division of Clinical Biochemistry Biocenter Innsbruck Medical University Fritz-Pregl-Strasse 3 A-6020 Innsbruck Austria Fax 43 512 507 2876 Tel 43 512 507 3521 E-mail Received 10 March 2005 revised 10 May 2005 accepted 26 May 2005 doi In humans eight types of histone H1 exist H1 Hit and H1oo all consisting of a highly conserved globular domain and less conserved N- and C-terminal tails. Although the precise functions of these isoforms are not yet understood and H1 subtypes have been found to be dispensable for mammalian development it is now clear that specific functions may be assigned to certain individual H1 subtypes. Moreover microsequence variations within the isoforms such as polymorphisms or mutations may have biological significance because of the high degree of sequence conservation of these proteins. This study used a hydrophilic interaction liquid chromatographic method to detect sequence variants within the subtypes. Two deviations from wild-type H1 sequences were found. In K562 erythroleukemic cells alanine at position 17 in was replaced by valine and in Raji B lymphoblastoid cells lysine at position 173 in was replaced by arginine. We confirmed these findings by DNA sequencing of the corresponding gene segments. In K562 cells a homozygous GCCfiGTC shift was found at codon 18 giving rise to Ala17Val because the initial methionine is removed in H1 histones. Raji cells showed a heterozygous AAAfiAGA codon change at position 174 in .