Biomedical subjects

Qiuping Hu

Publications and source records attributed to Qiuping Hu.

3 recordsLinked to original sources

PubMed2006

Altered cerebellar function in mice lacking CaV2.3 Ca2+ channel.

Voltage-dependent Ca(2+) channels play important roles in cerebellar functions including motor coordination and learning. Since abundant expression of Ca(V)2.3 Ca(2+) channel gene in the cerebellum was detected, we searched for possible deficits in the cerebellar functions in the Ca(V)2.3 mutant mice. Behavioral analysis detected in delayed motor learning in rotarod tests in mice heterozygous and homozygous for the Ca(V)2.3 gene disruption (Ca(V)2.3+/- and Ca(V)2.3-/-, respectively). Electrophysiological analysis of mutant mice revealed perplexing results: deficit in long-term depression (LTD) at the parallel fiber Purkinje cell synapse in Ca(V)2.3+/- mice but apparently normal LTD in Ca(V)2.3-/- mice. On the other hand, the number of spikes evoked by current injection in Purkinje cells under the current-clamp mode decreased in Ca(V)2.3 mutant mice in a gene dosage-dependent manner, suggesting that Ca(V)2.3 channel contributed to spike generation in Purkinje cells. Thus, Ca(V)2.3 channel seems to play some roles in cerebellar functions.

Action Potentials↗

PubMed2005

The carboxy-terminal tail region of human Cav2.1 (P/Q-type) channel is not an essential determinant for its subcellular localization in cultured neurones.

A recent report on the mechanism of synaptic targeting of Ca(v)2.2 channel suggested that this process depends upon the presence of long C-terminal tail and that protein interactions mediated by SH3-binding and PDZ-binding motifs in the tail region are important. To examine the possibility that C-terminal tail of the Ca(v)2.1 channel and the polyglutamine stretch therein are also involved in the mechanism for channel localization, we constructed several expression plasmids for human Ca(v)2.1 channel tagged with enhanced green fluorescent protein (EGFP) and introduced them into mouse hippocampal neuronal culture. HC construct encodes short version of Ca(v)2.1, and HS and HL encode Ca(v)2.1 channel with a long C-terminal tail, which contains polyglutamine tract of 13 (normal range) and 28 (SCA6 disease range) repeat units, respectively. Surprisingly, transfection with HC, HS, and HL gave essentially the same results: EGFP signal was observed in cell soma, dendrites, and the axon as well. Furthermore, mutation of the PDZ-binding motif located at the C-terminus of the long version of Ca(v)2.1, by adding FLAG tag, did not affect the localization patterns of HS and HL as well. Therefore, the C-terminal region is not indispensable for the subcellular localization of Ca(v)2.1 channel, nor expansion of polyglutamine length affected the localization of the channel. Thus, it is possible that the localization mechanism of Ca(v)2.1 channel is different from that of Ca(v)2.2, though these channels share various structural and functional characteristics.

Amino Acid Sequence↗

PubMed2002

Sequence and analysis of rice chromosome 4.

Rice is the principal food for over half of the population of the world. With its genome size of 430 megabase pairs (Mb), the cultivated rice species Oryza sativa is a model plant for genome research. Here we report the sequence analysis of chromosome 4 of O. sativa, one of the first two rice chromosomes to be sequenced completely. The finished sequence spans 34.6 Mb and represents 97.3% of the chromosome. In addition, we report the longest known sequence for a plant centromere, a completely sequenced contig of 1.16 Mb corresponding to the centromeric region of chromosome 4. We predict 4,658 protein coding genes and 70 transfer RNA genes. A total of 1,681 predicted genes match available unique rice expressed sequence tags. Transposable elements have a pronounced bias towards the euchromatic regions, indicating a close correlation of their distributions to genes along the chromosome. Comparative genome analysis between cultivated rice subspecies shows that there is an overall syntenic relationship between the chromosomes and divergence at the level of single-nucleotide polymorphisms and insertions and deletions. By contrast, there is little conservation in gene order between rice and Arabidopsis.

Arabidopsis↗