It has been shown that the monomethylated cap structure plays important roles in pre-mRNA splicing and nuclear export of RNA. As a candidate for the factor involved in these nuclear events we have previously purified an 80 kDa nuclear cap binding protein (NCBP) from a HeLa cell nuclear extract and isolated its full-length cDNA. In this report, in order to obtain a clue to the cellular functions of NCBP, we attempted to identify a factor(s) that interacts with NCBP. Using the yeast two-hybrid system we isolated three clones from a HeLa cell cDNA library. We designated the proteins encoded by these clones NIPs (NCBP interacting proteins). NIP1 and NIP2 have an RNP consensus-type RNA binding domain, whereas NIP3 contains a unique domain of Arg-Glu or Lys-Glu dipeptide repeats. We also show that NCBP requires NIP1 for binding to the cap structure. Possible roles of NIPs in cap-dependent nuclear processes are discussed.

Abstract. We aim to test the feasibility of using near-infrared spectroscopy (NIRS) for indirect measurement of human saliva secretion in response to taste stimuli for potential application to organoleptic testing. We use an NIRS system to measure extracranial hemodynamics (Hb-signals around the temples) of healthy participants when taste stimuli are taken in their mouths. First, the Hb-signals and volume of expelled saliva (stimulated by distilled-water or sucrose-solution intake) are simultaneously measured and large Hb-signal changes in response to the taste stimuli (Hb-responses) are found. Statistical analysis show that both the Hb response and saliva volume are larger for the sucrose solution than for the distilled water with a significant correlation between them (r = 0.81). The effects of swallowing on the Hb-signals are investigated. Similar Hb responses, differing from the sucrose solution and distilled water, are obtained even though the participants swallow the mouth contents. Finally, functional magnetic resonance imaging is used to identify possible sources of the Hb signals corresponding to salivation. Statistical analysis indicates similar responses in the extracranial regions, mainly around the middle meningeal artery. In conclusion, the identified correlation between extracranial hemodynamics and the saliva volume suggests that NIRS is applicable to the measurement of hemodynamic signals accompanying stimulated saliva secretion. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

Interactions between the nuclear matrix and special regions of chromosomal DNA called matrix attachment regions (MARs) have been implicated in various nuclear functions. We have identified a novel protein from wheat, AT hookcontaining MAR binding protein1 (AHM1), that binds preferentially to MARs. A multidomain protein, AHM1 has the special combination of a J domain-homologous region and a Zn finger-like motif (a J-Z array) and an AT hook. For MAR binding, the AT hook at the C terminus was essential, and an internal portion containing the Zn finger-like motif was additionally required in vivo. AHM1 was found in the nuclear matrix fraction and was localized in the nucleoplasm. AHM1 fused to green fluorescent protein had a speckled distribution pattern inside the nucleus. AHM1 is most likely a nuclear matrix component that functions between intranuclear framework and MARs. J-Z arrays can be found in a group of (hypothetical) proteins in plants, which may share some functions, presumably to recruit specific Hsp70 partners as co-chaperones. INTRODUCTIONThe nuclear matrix, operationally defined, is the dynamic fibrogranular structure forming the skeletal framework that surrounds and penetrates the interphase nucleus; it has been implicated in most nuclear functions, including replication, repair, transcription, RNA processing, and RNA transport (Berezney and Jeon, 1995). The chromosomal DNAs are known to be associated with the nuclear matrix at specific regions called matrix attachment regions (MARs) and are thereby thought to be organized into topologically constrained loops, each of which represents a sort of functional or structural domain (or both) (Laemmli et al., 1992;Bode et al., 1996). In animals, interactions between the nuclear matrix and MARs have also been shown to be involved in DNA replication and repair and in various aspects of gene regulation, thus playing a key role in the essential functions of the nucleus (Boulikas, 1995;Bode et al., 1996).MARs consist of AT-rich sequences extending over at least a few hundred base pairs and containing various ATrich motifs as well as structural motifs such as base-unpairing regions and intrinsically curved portions (Boulikas, 1995). In animals, MAR binding activity has been found in a wide range of structurally and functionally diverse proteins (listed in Boulikas, 1995). These include topoisomerase II (Adachi et al., 1989); filament proteins such as lamins and NuMA (Ludérus et al., 1992(Ludérus et al., , 1994; ARBP, identical to a methylated CpG binding protein (von Kries et al., 1991;Weitzel et al., 1997); hnRNP-U/SAF1, an RNA binding protein involved in RNA processing (Fackelmayer et al., 1994;von Kries et al., 1994); SATB1, a tissue-specific transcription factor with high affinity for base-unpairing regions (Dickinson et al., 1992; de Belle et al., 1998); and architectural chromatin proteins such as histone H1 and HMG-I/Y (Zhao et al., 1993).In plants, MARs have been found in intergenic regions, often in or close to the regulatory regions of genes, and clo...

HBP-1a(17) is representative of a group of plant bZIP-type transcription factors which includes HBP-1a proteins and G-box-binding factors. We found kinase activity in wheat nuclear extract that phosphorylated HBP-1a(17). Experiments using recombinant HBP-1a(17) derivatives as substrates revealed that all three of the Ser residues in the basic region, Ser-261, Ser-265, and Ser-269, were phosphorylated in a Ca(2+)-stimulated manner. DNA-binding analysis of mutants with a Ser-to-Glu change, prepared to mimic the phosphorylated proteins, indicated that introduction of a negative charge at position 265 or 269 prevents HBP-1a(17) from binding DNA not only in the homodimer of mutants but also in heterodimers with a wild-type protein. It is therefore suggested that the phosphorylation regulates the function of HBP-1a(17) at least at the level of DNA binding. Since Ser-265 and Ser-269 are highly conserved among the plant bZIP-type factors known to date, a common Ca(2+)-mediated regulatory mechanism may exert an effect on the bZIP-type factors through phosphorylation of these conserved Ser residues.

Interactions between the nuclear matrix and special regions of chromosomal DNA called matrix attachment regions (MARs) have been implicated in various nuclear functions. We have identified a novel protein from wheat, AT hookcontaining MAR binding protein1 (AHM1), that binds preferentially to MARs. A multidomain protein, AHM1 has the special combination of a J domain-homologous region and a Zn finger-like motif (a J-Z array) and an AT hook. For MAR binding, the AT hook at the C terminus was essential, and an internal portion containing the Zn finger-like motif was additionally required in vivo. AHM1 was found in the nuclear matrix fraction and was localized in the nucleoplasm. AHM1 fused to green fluorescent protein had a speckled distribution pattern inside the nucleus. AHM1 is most likely a nuclear matrix component that functions between intranuclear framework and MARs. J-Z arrays can be found in a group of (hypothetical) proteins in plants, which may share some functions, presumably to recruit specific Hsp70 partners as co-chaperones. INTRODUCTIONThe nuclear matrix, operationally defined, is the dynamic fibrogranular structure forming the skeletal framework that surrounds and penetrates the interphase nucleus; it has been implicated in most nuclear functions, including replication, repair, transcription, RNA processing, and RNA transport (Berezney and Jeon, 1995). The chromosomal DNAs are known to be associated with the nuclear matrix at specific regions called matrix attachment regions (MARs) and are thereby thought to be organized into topologically constrained loops, each of which represents a sort of functional or structural domain (or both) (Laemmli et al., 1992;Bode et al., 1996). In animals, interactions between the nuclear matrix and MARs have also been shown to be involved in DNA replication and repair and in various aspects of gene regulation, thus playing a key role in the essential functions of the nucleus (Boulikas, 1995;Bode et al., 1996).MARs consist of AT-rich sequences extending over at least a few hundred base pairs and containing various ATrich motifs as well as structural motifs such as base-unpairing regions and intrinsically curved portions (Boulikas, 1995). In animals, MAR binding activity has been found in a wide range of structurally and functionally diverse proteins (listed in Boulikas, 1995). These include topoisomerase II (Adachi et al., 1989); filament proteins such as lamins and NuMA (Ludérus et al., 1992(Ludérus et al., , 1994; ARBP, identical to a methylated CpG binding protein (von Kries et al., 1991;Weitzel et al., 1997); hnRNP-U/SAF1, an RNA binding protein involved in RNA processing (Fackelmayer et al., 1994;von Kries et al., 1994); SATB1, a tissue-specific transcription factor with high affinity for base-unpairing regions (Dickinson et al., 1992; de Belle et al., 1998); and architectural chromatin proteins such as histone H1 and HMG-I/Y (Zhao et al., 1993).In plants, MARs have been found in intergenic regions, often in or close to the regulatory regions of genes, and clo...