Yeast hnRNP K-like genes are involved in regulation of the telomeric position effect and telomere length.
Mammalian heterogeneous nuclear ribonucleoprotein K (hnRNP K) is an RNA- and DNA-binding protein implicated in the regulation of gene expression processes. To better understand its function, we studied two Saccharomyces cerevisiae homologues of the human hnRNP K, PBP2 and HEK2 (heterogeneous nuclear RNP K-like gene). pbp2Delta and hek2Delta mutations inhibited expression of a marker gene that was inserted near telomere but not at internal chromosomal locations. The telomere proximal to the ectopic marker gene became longer, while most of the other telomeres were not altered in the double mutant cells. We provide evidence that telomere elongation might be the primary event that causes enhanced silencing of an adjacent reporter gene. The telomere lengthening could, in part, be explained by the inhibitory effect of hek2Delta mutation on the telomeric rapid deletion pathway. Hek2p was detected in a complex with chromosome regions proximal to the affected telomere, suggesting a direct involvement of this protein in telomere maintenance. These results identify a role for hnRNP K-like genes in the structural and functional organization of telomeric chromatin in yeast.
Denisenko
Oleg
O
Division of Nephrology, Department of Medicine, University of Washington, Seattle, Washington 98195, USA. odenis@u.washington.edu
Bomsztyk
Karol
K
D000595:Amino Acid Sequence; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D020868:Gene Silencing / Q000502:physiology; D005800:Genes, Fungal; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D008969:Molecular Sequence Data; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D016615:Telomere / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
D005656:Fungal Proteins; C443676:HEK2 protein, S cerevisiae; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C443675:PBP2 protein, S cerevisiae; D012261:Ribonucleoproteins; C084122:SIR3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D015534:Trans-Activators